diff --git a/more/free-programming-playgrounds.md b/more/free-programming-playgrounds.md
index caf557540..d41a96e63 100644
--- a/more/free-programming-playgrounds.md
+++ b/more/free-programming-playgrounds.md
@@ -1,5 +1,6 @@
 ### Index
 
+* [Algorithms](#algorithms)
 * [APL](#apl)
 * [Assembly](#assembly)
 * [Bash](#bash)
@@ -53,6 +54,12 @@
 * [Vim](#vim)
 
 
+### Algorithms
+
+* [Data Structures Visualization](https://www.cs.usfca.edu/~galles/visualization/Algorithms.html) - David Galles
+* [The Algorithm Visualizer](https://algorithm-visualizer.org)
+
+
 ### APL
 
 * [APLgolf](https://razetime.github.io/APLgolf)