diff --git a/journal/2021-04-21.md b/journal/2021-04-21.md
index c84ec30f8..6bd23d298 100644
--- a/journal/2021-04-21.md
+++ b/journal/2021-04-21.md
@@ -1,3 +1,4 @@
 # 2021-04-21
 
-- [[open source monitoring]]
\ No newline at end of file
+- [[open source monitoring]]
+- [[missing semester]]
\ No newline at end of file
diff --git a/missing-semester.md b/missing-semester.md
new file mode 100644
index 000000000..6f9baf73e
--- /dev/null
+++ b/missing-semester.md
@@ -0,0 +1,4 @@
+# missing semester
+
+- [[go]] https://missing.csail.mit.edu/
+