diff --git a/doc/src/SUMMARY.md b/doc/src/SUMMARY.md
index 5cb91bd01f07d..19070c0722b1c 100644
--- a/doc/src/SUMMARY.md
+++ b/doc/src/SUMMARY.md
@@ -12,6 +12,6 @@
 
 ---
 
-# Challenges
-- [Core Transmutation](./core-transmutation.md)
-- [Memory safety of core intrinsics](./intrinsics-memory.md)
+- Challenges
+  - [Core Transmutation](./challenges/0001-core-transmutation.md)
+  - [Memory safety of core intrinsics](./challenges/0002-intrinsics-memory.md)
diff --git a/doc/src/core-transmutation.md b/doc/src/challenges/0001-core-transmutation.md
similarity index 100%
rename from doc/src/core-transmutation.md
rename to doc/src/challenges/0001-core-transmutation.md
diff --git a/doc/src/intrinsics-memory.md b/doc/src/challenges/0002-intrinsics-memory.md
similarity index 100%
rename from doc/src/intrinsics-memory.md
rename to doc/src/challenges/0002-intrinsics-memory.md