diff --git a/bookmarks.xbel b/bookmarks.xbel
index db16981..83e0c64 100755
--- a/bookmarks.xbel
+++ b/bookmarks.xbel
@@ -720,9 +720,6 @@
 <bookmark href="https://rockthejvm.com/" id="272">
   <title>Rock the JVM</title>
 </bookmark>
-<bookmark href="https://www.symmetrymagazine.org/article/january-2015/how-to-build-your-own-particle-detector" id="273">
-  <title>How to build your own particle detector | symmetry magazine</title>
-</bookmark>
 <bookmark href="https://www.wxcharts.com/?panel=default&amp;model=gfs,gfs,gfs,gfs&amp;region=slovakia&amp;chart=overview,850temp,accprecip,2mtemp&amp;run=12&amp;step=003&amp;plottype=10&amp;lat=50.060&amp;lon=14.446&amp;skewtstep=0" id="283">
   <title>WXCharts v1.0.25</title>
 </bookmark>