The Hal-Saflieni Hypogeum is one of the most interesting places in Malta. There a lot of interesting and aslo some funny theories about it, because it's so fantastic that everybody fiction his own explanation about the its functions. The scientist think this is a prehistoric necropolis. Some people say they saw alliens inside :). For me it was a fasctinating experience to go there. I didn't know that have to register for the visit (the visits are limited because of the climatic regime of the monument) so I just went there one sunday without any preliminary registration. After I found it (it wasn't easy) they said I can't go inaside because I don't have registration. But I had the chance that I was alone, I'm a girl ;), I wasn't speaking english very well but was asking a lot of questions and was so unhappy because I was leaving Malta next day, and also there weren't namy tourists at that day, so the guides let me in even on a reduce price (a student price or something like that) and were explaning a lot of things only for me (the others of the group weren't so interested by the wall-paintings and some other things). I thinks this was one of my luckyest days :)