diff --git a/bookmarks.xbel b/bookmarks.xbel
index 1f63e0a..9d3f08c 100755
--- a/bookmarks.xbel
+++ b/bookmarks.xbel
@@ -654,9 +654,6 @@
 <bookmark href="https://www.in-pocasi.cz/predpoved-pocasi/cz/stredocesky/jinocany-4769/" id="210">
   <title>Počasí - Jinočany, předpověď na 10 dní | In-počasí</title>
 </bookmark>
-<bookmark href="https://www.symmetrymagazine.org/article/january-2015/how-to-build-your-own-particle-detector" id="211">
-  <title>How to build your own particle detector | symmetry magazine</title>
-</bookmark>
 <bookmark href="https://postgrespro.ru/education/courses/DBA1" id="212">
   <title>DBA1</title>
 </bookmark>