http://revach.net/article.php?id=3920

Section: Revach   Category: Lists
A Closer Look At The 5 Terrible Events That Happened On 17 Tammuz
The Mishna lists five terrible events that happened on Tisha B'Av.  The Seder HaYom says, "who cannot fall on the floor and weep from even a single one these events let alone all five."

Not all of the events are clear when and where they happened, and by who.  To see a full list and the details of the various opinions click here for Revach Lists.