Well said klm-md11
Do people out there really imagine that all airports are open 24hrs?
LGMT does not have a lot of movements even during the day, thus the number of ATC staff is limited.
It's happened before, and it'll happen again. I was on the flight deck of a PIA flight many years ago, commencing descent into Tirana (Albania). Despite Belgrade calling them on the landline and numerous calls over the radio, they did not respond. The captain did a low pass, and one by one the lights started to come on. It seems that the transport to take the staff home (no private cars allowed in those days) had not turned up, so they had decided to have a party in the tower, and overslept. Mind you it was 0530!