Whats it called when...?

Question

ages ago like 1800, some people convinced a town to kill themselves becoz they said it was better up there than on earth... what is that called?

Answer 1

I believe you may be thinking of the Jonestown Massacre. One of the biggest mass suicides in the U.S. But this happenned in 1978. If that's not what you are looking for, I suggest looking at wikipedia... very useful :)