Our periodicvideos YouTube channel reached 50,000 subscribers last night.
The historic subscription came from someone in Croatia... I've emailed the person to try and find out more about them.
I'm also working on a special video to mark the milestone. That will be coming soon.
In the meantime, here's bit of a favourite video about our work covering the elements.
PS: In the same evening, our physics channel Sixty Symbols reached its 40,000th subscriber!