diff --git a/webui/README.md b/webui/README.md
index 6bd97d807..07cc2a76c 100644
--- a/webui/README.md
+++ b/webui/README.md
@@ -3,8 +3,7 @@
 This is Ray's Web UI. It consists of two components:
 
 * The **frontend** is a [Polymer](https://www.polymer-project.org/1.0/) app that
-  uses [google-charts](https://elements.polymer-project.org/elements/google-chart)
-  for visualization.
+  uses [D3](https://d3js.org/) for visualization.
 * The **backend** is a Python 3 websocket server (see `backend/ray_ui.py`) that
   connects to Redis and potentially Ray.
 
diff --git a/webui/backend/ray_ui.py b/webui/backend/ray_ui.py
index 93b6cbaab..d0dbb5d96 100644
--- a/webui/backend/ray_ui.py
+++ b/webui/backend/ray_ui.py
@@ -4,6 +4,8 @@ import asyncio
 import binascii
 from collections import defaultdict
 import json
+import numpy as np
+import redis
 import websockets
 
 parser = argparse.ArgumentParser(description="parse information for the web ui")
@@ -31,36 +33,87 @@ def key_to_hex_identifiers(key):
   task_id = hex_identifier(key[offset:(offset + IDENTIFIER_LENGTH)])
   return worker_id, task_id
 
+worker_ids = []
 
-async def hello(websocket, path):
-  conn = await aioredis.create_connection((redis_ip_address, redis_port), loop=loop)
+async def handle_get_recent_tasks(websocket, redis_conn, num_tasks):
+  keys = await redis_conn.execute("keys", "event_log:*")
+  if len(keys) == 0:
+    # There are no tasks, so send a message to the client saying so.
+    await websocket.send(json.dumps({"num_tasks": 0}))
+  else:
+    timestamps = []
+    contents = []
+    for key in keys:
+      content = await redis_conn.execute("lrange", key, "0", "-1")
+      contents.append(json.loads(content[0].decode()))
+      timestamps += [timestamp for (timestamp, task, kind, info) in contents[-1] if task == "ray:task"]
 
+    timestamps.sort()
+    time_cutoff = timestamps[(-2 * num_tasks):][0]
+
+    max_time = timestamps[-1]
+    min_time = time_cutoff - (max_time - time_cutoff) * 0.1
+    max_time = max_time + (max_time - time_cutoff) * 0.1
+
+    task_data = []
+    for i in range(len(keys)):
+      worker_id, task_id = key_to_hex_identifiers(keys[i])
+      data = contents[i]
+      if worker_id not in worker_ids:
+        worker_ids.append(worker_id)
+      worker_index = worker_ids.index(worker_id)
+
+      task_times = [timestamp for (timestamp, task, kind, info) in data if task == "ray:task"]
+      if task_times[1] <= time_cutoff:
+        continue
+
+      task_get_arguments_times = [timestamp for (timestamp, task, kind, info) in data if task == "ray:task:get_arguments"]
+      task_execute_times = [timestamp for (timestamp, task, kind, info) in data if task == "ray:task:execute"]
+      task_store_outputs_times = [timestamp for (timestamp, task, kind, info) in data if task == "ray:task:store_outputs"]
+      task_data.append({"task": task_times,
+                        "get_arguments": task_get_arguments_times,
+                        "execute": task_execute_times,
+                        "store_outputs": task_store_outputs_times,
+                        "worker_index": worker_index})
+    reply = {"min_time": min_time,
+             "max_time": max_time,
+             "num_tasks": len(task_data),
+             "task_data": task_data}
+    await websocket.send(json.dumps(reply))
+
+async def serve_requests(websocket, path):
+  redis_conn = await aioredis.create_connection((redis_ip_address, redis_port), loop=loop)
+
+  # We loop infinitely because otherwise the websocket will be closed.
   while True:
     command = json.loads(await websocket.recv())
     print("received command {}".format(command))
 
+    if command["command"] == "get-recent-tasks":
+      await handle_get_recent_tasks(websocket, redis_conn, command["num"])
+
     if command["command"] == "get-workers":
       result = []
-      workers = await conn.execute("keys", "WorkerInfo:*")
+      workers = await redis_conn.execute("keys", "WorkerInfo:*")
       for key in workers:
-        content = await conn.execute("hgetall", key)
+        content = await redis_conn.execute("hgetall", key)
         worker_id = key_to_hex_identifier(key)
         result.append({"worker": worker_id, "export_counter": int(content[1])})
       await websocket.send(json.dumps(result))
     elif command["command"] == "get-clients":
       result = []
-      clients = await conn.execute("keys", "CL:*")
+      clients = await redis_conn.execute("keys", "CL:*")
       for key in clients:
-        content = await conn.execute("hgetall", key)
+        content = await redis_conn.execute("hgetall", key)
         result.append({"client": hex_identifier(content[1]),
                        "node_ip_address": content[3].decode(),
                        "client_type": content[5].decode()})
       await websocket.send(json.dumps(result))
     elif command["command"] == "get-objects":
       result = []
-      objects = await conn.execute("keys", "OI:*")
+      objects = await redis_conn.execute("keys", "OI:*")
       for key in objects:
-        content = await conn.execute("hgetall", key)
+        content = await redis_conn.execute("hgetall", key)
         result.append({"object_id": hex_identifier(content[1]),
                        "hash": hex_identifier(content[3]),
                        "data_size": content[5].decode()})
@@ -73,18 +126,18 @@ async def hello(websocket, path):
       await websocket.send(json.dumps({"object_id": "none"}))
     elif command["command"] == "get-tasks":
       result = []
-      tasks = await conn.execute("keys", "TT:*")
+      tasks = await redis_conn.execute("keys", "TT:*")
       for key in tasks:
-        content = await conn.execute("hgetall", key)
+        content = await redis_conn.execute("hgetall", key)
         result.append({"task_id": key_to_hex_identifier(key),
                        "state": int(content[1]),
                        "node_id": hex_identifier(content[3])})
       await websocket.send(json.dumps(result))
     elif command["command"] == "get-timeline":
       tasks = defaultdict(list)
-      for key in await conn.execute("keys", "event_log:*"):
+      for key in await redis_conn.execute("keys", "event_log:*"):
         worker_id, task_id = key_to_hex_identifiers(key)
-        content = await conn.execute("lrange", key, "0", "-1")
+        content = await redis_conn.execute("lrange", key, "0", "-1")
         data = json.loads(content[0].decode())
         begin_and_end_time = [timestamp for (timestamp, task, kind, info) in data if task == "ray:task"]
         tasks[worker_id].append({"task_id": task_id,
@@ -93,9 +146,9 @@ async def hello(websocket, path):
       await websocket.send(json.dumps(tasks))
     elif command["command"] == "get-events":
       result = []
-      for key in await conn.execute("keys", "event_log:*"):
+      for key in await redis_conn.execute("keys", "event_log:*"):
         worker_id, task_id = key_to_hex_identifiers(key)
-        answer = await conn.execute("lrange", key, "0", "-1")
+        answer = await redis_conn.execute("lrange", key, "0", "-1")
         assert len(answer) == 1
         events = json.loads(answer[0].decode())
         result.extend([{"worker_id": worker_id,
@@ -109,7 +162,7 @@ if __name__ == "__main__":
   redis_address = args.redis_address.split(":")
   redis_ip_address, redis_port = redis_address[0], int(redis_address[1])
 
-  start_server = websockets.serve(hello, "localhost", args.port)
+  start_server = websockets.serve(serve_requests, "localhost", args.port)
 
   loop.run_until_complete(start_server)
   loop.run_forever()
diff --git a/webui/index.html b/webui/index.html
index d91861d7c..97d1ed5fe 100644
--- a/webui/index.html
+++ b/webui/index.html
@@ -15,6 +15,8 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
     <meta name="generator" content="Polymer Starter Kit">
     <meta name="viewport" content="width=device-width, minimum-scale=1, initial-scale=1, user-scalable=yes">
 
+    <script src="https://d3js.org/d3.v4.min.js"></script>
+
     <title>Ray UI</title>
     <meta name="description" content="A web UI for Ray">
 
diff --git a/webui/src/ray-app.html b/webui/src/ray-app.html
index 218873458..beecbcfbb 100644
--- a/webui/src/ray-app.html
+++ b/webui/src/ray-app.html
@@ -75,6 +75,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
           <a name="tasks" href="/tasks">Tasks</a>
           <a name="events" href="/events">Events</a>
           <a name="timeline" href="/timeline">Timeline</a>
+          <a name="recent-tasks" href="/recent-tasks">Recent Tasks</a>
         </iron-selector>
       </app-drawer>
 
@@ -98,6 +99,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
           <ray-tasks name="tasks"></ray-tasks>
           <ray-events name="events"></ray-events>
           <ray-timeline name="timeline"></ray-timeline>
+          <ray-recent-tasks name="recent-tasks"></ray-recent-tasks>
           <ray-view404 name="view404"></ray-view404>
         </iron-pages>
       </app-header-layout>
diff --git a/webui/src/ray-recent-tasks.html b/webui/src/ray-recent-tasks.html
new file mode 100644
index 000000000..f8abdf0e4
--- /dev/null
+++ b/webui/src/ray-recent-tasks.html
@@ -0,0 +1,76 @@
+<link rel="import" href="../bower_components/polymer/polymer.html">
+<link rel="import" href="shared-styles.html">
+
+<script src="recent-tasks.js"></script>
+
+<dom-module id="ray-recent-tasks">
+  <template>
+    <style include="shared-styles">
+      :host {
+        display: block;
+
+        padding: 10px;
+      }
+      rect:hover
+      {
+        opacity: 0.5;
+      }
+
+    </style>
+
+    <div class="card">
+      <h1>Ray Recent Tasks</h1>
+      <input value=100 id="input_num_tasks"></input>
+      <button id="refresh_button">Refresh</button>
+      <br></br>
+      <svg id="recent_tasks"></svg>
+    </div>
+  </template>
+
+  <script>
+    var redis_address = "ws://127.0.0.1:8888";
+
+    var width = 1000,
+        height = 500,
+        row_height = 50,
+        num_workers = 8;
+
+    Polymer({
+      is: 'ray-recent-tasks',
+      ready: function() {
+
+        var self = this;
+        var socket = new WebSocket(redis_address);
+
+        recent_tasks = new RecentTasks(self.$.recent_tasks, {
+          "width": width, "height": height,
+        });
+
+        socket.onopen = function() {
+          socket.send(JSON.stringify({"command": "get-recent-tasks", "num": 100}));
+        }
+
+        socket.onmessage = function(messageEvent) {
+          var task_info = JSON.parse(messageEvent.data);
+          console.log(task_info.num_tasks);
+          if (task_info["num_tasks"] == 0) {
+            console.log("No tasks yet.");
+            return;
+          }
+          recent_tasks.draw_new_tasks(task_info);
+        }
+
+        socket.onclose = function(closeEvent) {
+          console.log(closeEvent)
+        }
+
+        d3.select(this.$.refresh_button)
+            .on("click", function () {
+              recent_tasks.erase();
+              var num_tasks_to_get = self.$.input_num_tasks.value;
+              socket.send(JSON.stringify({"command": "get-recent-tasks", "num": parseInt(num_tasks_to_get)}));
+            });
+      }
+    });
+  </script>
+</dom-module>
diff --git a/webui/src/recent-tasks.js b/webui/src/recent-tasks.js
new file mode 100644
index 000000000..2f5e87d8d
--- /dev/null
+++ b/webui/src/recent-tasks.js
@@ -0,0 +1,74 @@
+RecentTasks = function(elem, options) {
+  var self = this;
+
+  this.options = options;
+  var barHeight = 25;
+
+  var svg = d3.select(elem)
+      .attr("width", this.options.width)
+      .attr("height", this.options.height);
+
+  this.draw_new_tasks = function(task_info) {
+    this.task_info = task_info;
+    var x = d3.scaleLinear()
+        .domain([task_info.min_time, task_info.max_time])
+        .range([-1, width + 1]);
+
+    var xAxis = d3.axisBottom(x)
+        .tickSize(-height);
+
+    var gx = svg.append("g")
+        .attr("class", "axis axis--x")
+        .attr("transform", "translate(0," + (height - 10) + ")")
+        .call(xAxis);
+
+    var task_rects = svg.append("g").attr("class", "task_rects");
+    var get_arguments_rects = svg.append("g").attr("class", "get_arguments_rects");
+    var execute_rects = svg.append("g").attr("class", "execute_rects");
+    var store_outputs_rects = svg.append("g").attr("class", "store_outputs_rects");
+
+    task_rects.selectAll("rect")
+        .data(this.task_info.task_data)
+      .enter()
+      .append("rect")
+        .attr("x", function (d) { return x(d.task[0]); })
+        .attr("y", function (d) { return (d.worker_index + 1) * barHeight; })
+        .attr("width", function (d) { return x(d.task[1]) - x(d.task[0]); })
+        .attr("height", function (d) { return barHeight - 1; })
+        .attr("fill", "orange")
+
+    get_arguments_rects.selectAll("rect")
+        .data(this.task_info.task_data)
+      .enter()
+      .append("rect")
+        .attr("x", function (d) { return x(d.get_arguments[0]); })
+        .attr("y", function (d) { return (d.worker_index + 1) * barHeight + 1; })
+        .attr("width", function (d) { return x(d.get_arguments[1]) - x(d.get_arguments[0]); })
+        .attr("height", function (d) { return barHeight - 3; })
+        .attr("fill", "black")
+
+    execute_rects.selectAll("rect")
+        .data(this.task_info.task_data)
+      .enter()
+      .append("rect")
+        .attr("x", function (d) { return x(d.execute[0]); })
+        .attr("y", function (d) { return (d.worker_index + 1) * barHeight + 1; })
+        .attr("width", function (d) { return x(d.execute[1]) - x(d.execute[0]); })
+        .attr("height", function (d) { return barHeight - 3; })
+        .attr("fill", "blue")
+
+    store_outputs_rects.selectAll("rect")
+        .data(this.task_info.task_data)
+      .enter()
+      .append("rect")
+        .attr("x", function (d) { return x(d.store_outputs[0]); })
+        .attr("y", function (d) { return (d.worker_index + 1) * barHeight + 1; })
+        .attr("width", function (d) { return x(d.store_outputs[1]) - x(d.store_outputs[0]); })
+        .attr("height", function (d) { return barHeight - 3; })
+        .attr("fill", "green")
+  }
+
+  this.erase = function() {
+    svg.selectAll("g").remove()
+  }
+}