Throughout history, numerous civilizations, both local and foreign, settled in and ruled the Arab World each of them leaving its trace of monuments and landmarks. This made the regions within the Arab World a mosaic of remnants from most of the civilizations of the Old World. In some countries, you can find Ancient Roman temples next to an Umayyad palace, or a Crusader castle in a Mamluk Old Town, or even an Eastern Orthodox Church next to an Ottoman mosque.