Ibiza is a spanish Island directly south of Barcelonna. Go find a map and find Barcelona Spain, then use your finger and go south from there... there are 2 islands pretty close, Ibiza is one of them.
Average age is like 15 there, everyone seemed to be underage (under 18), so be aware of that. Alot of snotty english wankers and someone else said, and quite a few german/scanadianvians.
The other island to the right of Ibiza is still a party island but a bit more older crowd, 20 somthing ish...
and yes all teh greek islands are insane as well, but Ibiza is the main one.
You can fly down there or take a 2 or 3 hour ferry trip from Barcelonna to get there.
You should check it out at least once in your life time if you ask me
😛