Mount Sinai

The Monastery of St. Catherine, (http://www.sinaimonastery.com/) at the foot of the mountain, is the easier of the two destinations here. Looking more like a fortress than a church, access is through a massive iron gate shut for the night and opened in the morning from 9 AM to 12 AM only daily except Friday and Sunday. Note that the monastery observes the Greek Orthodox rites and is thus also closed for Christmas and Easter as calculated by the Greek Orthodox calendar. It was declared a UNESCO World Heritage site in 2002.

Church of St. Catherine
The main church of the complex, completed in 551.
Basilica
Famous for a mosaic of the Transfiguration as of 2008/07/Feb 2011 in restoration and not in public.
Moses' Well
A spring that supplies water to the monastery and, according to legend, the location where Moses met his wife for the first time.
Library
One of the greatest repositories of ancient manuscripts in the world second only to the Vatican, housing over 4500 rare volumes. No access without special permission granted only to VIPs and bona fide scholars.
Ossuary
This morbid charnel house contains the skulls of 1400 years' worth of monks who have lived and died here.

On Feb 2011, there is only a few parts of the monastery which are accessible to tourists.There is also a small museum mainly about Byzantine icons / tempera on wood. You need to make a 25egp donation as entrance fee but it is worth it.

A guide for the monastery could start at 100egp but you could/must bargain.