diff --git a/.gitmodules b/.gitmodules
index 5a087b626e13218bc390c7bb8d58e00ac794566d..f4d8174127d30f1dce157daec98fc6f52c3ff29a 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -22,9 +22,6 @@
 [submodule "mods/xdecor"]
 	path = mods/xdecor
 	url = https://git.tchncs.de/Illuna-Minetest/xdecor.git
-[submodule "mods/caverealms"]
-	path = mods/caverealms
-	url = https://git.tchncs.de/Illuna-Minetest/caverealms.git
 [submodule "mods/wardrobe"]
 	path = mods/wardrobe
 	url = https://git.tchncs.de/Illuna-Minetest/wardrobe.git
@@ -140,12 +137,18 @@
 [submodule "mods/illuna_extras"]
 	path = mods/illuna_extras
 	url = https://git.tchncs.de/Illuna-Minetest/illuna_extras
-[submodule "mods/fun_caves"]
-	path = mods/fun_caves
-	url = https://github.com/duane-r/fun_caves
 [submodule "mods/farming"]
 	path = mods/farming
 	url = https://git.tchncs.de/Illuna-Minetest/farming
 [submodule "mods/boats"]
 	path = mods/boats
 	url = https://git.tchncs.de/Illuna-Minetest/boats
+[submodule "mods/fun_caves"]
+	path = mods/fun_caves
+	url = https://git.tchncs.de/Illuna-Minetest/fun_caves
+[submodule "mods/underworlds"]
+	path = mods/underworlds
+	url = https://git.tchncs.de/Illuna-Minetest/underworlds
+[submodule "mods/caverealms"]
+	path = mods/caverealms
+	url = https://git.tchncs.de/Illuna-Minetest/caverealms
diff --git a/mods/caverealms b/mods/caverealms
index be67d10792ce97dfddf29dfc0fb0180a24cfd955..981ea83e5c0affb4e11a6902368600f889ec492b 160000
--- a/mods/caverealms
+++ b/mods/caverealms
@@ -1 +1 @@
-Subproject commit be67d10792ce97dfddf29dfc0fb0180a24cfd955
+Subproject commit 981ea83e5c0affb4e11a6902368600f889ec492b
diff --git a/mods/fun_caves b/mods/fun_caves
index f1f0abcc166d3bb94c202543d7eec492d3d26949..133e66ad38389b4c500e7f90a2b548624ef5fa3e 160000
--- a/mods/fun_caves
+++ b/mods/fun_caves
@@ -1 +1 @@
-Subproject commit f1f0abcc166d3bb94c202543d7eec492d3d26949
+Subproject commit 133e66ad38389b4c500e7f90a2b548624ef5fa3e
diff --git a/mods/underworlds b/mods/underworlds
new file mode 160000
index 0000000000000000000000000000000000000000..580dd54d701cdfd3358d0bb9fba4decd9ce9b74f
--- /dev/null
+++ b/mods/underworlds
@@ -0,0 +1 @@
+Subproject commit 580dd54d701cdfd3358d0bb9fba4decd9ce9b74f