St. Catherine's Monastery, which was built in the 6th century by Byzantine Emperor Justinian I, is said to be the oldest continuously functioning Christian monastery in existence. It is still home to a community of the Greek Orthodox monks who guard the compound and its contents, and operate the nearby guesthouse and restaurant. It's built around the Chapel of the Burning Bush, which dates to the 4th century A.D. and is said to be built on the site of the original burning bush. Tradition holds that the bush growing there today is, in fact, the very bush from which God spoke to Moses and told him that he was standing on holy ground. One of the things that makes this place special is the collection of paintings and art that was untouched by the iconoclastic hysteria that gripped the church in the 8th and 9th centuries. The second must-see within the compound is the museum of relics and icons. Entrance is LE50 ($9.10/£4.65), payable at the museum inside the walls of the monastery compound, which is more than reasonable considering the array of perfectly preserved early manuscripts, richly decorated reliquaries, painted icons, and embroidery. Finally, don't miss the Church of St. Catherine (more properly known as the Basilica of the Transfiguration), which includes a small sampling of the monastery's rich collection of icons, as well as one of the best preserved Byzantine mosaics in the world over the apse. Women and men should dress modestly.