diff --git a/rtchallenge/src/lib.rs b/rtchallenge/src/lib.rs
index a20a328..c3b835f 100644
--- a/rtchallenge/src/lib.rs
+++ b/rtchallenge/src/lib.rs
@@ -45,5 +45,6 @@ pub mod prelude {
         shapes::{plane, sphere, test_shape},
         transformations::view_transform,
         tuples::{point, vector, Color},
+        world::{World, WorldBuilder},
     };
 }