diff --git a/doc/examples/plot_pyramid.py b/doc/examples/plot_pyramid.py
index cacf0689..218e86b1 100644
--- a/doc/examples/plot_pyramid.py
+++ b/doc/examples/plot_pyramid.py
@@ -3,7 +3,10 @@
 Build image pyramids
 ====================
 
-This example shows how to build image pyramids.
+The `build_gauassian_pyramid` function takes an image and yields successive
+images shrunk by a constant scale factor. Image pyramids are often used, e.g.,
+to implement algorithms for denoising, texture discrimination, and scale-
+invariant detection.
 """
 
 import numpy as np