Abu Dhabi’s most iconic structure has to be the Sheikh Zayed Mosque: a $550 million white stone, gold and crystal confection capped by 82 domes and four graceful minarets rising 350 feet over a grand courtyard festooned with the world’s largest marble mosaic. Arrive early to avoid the later-morning heat and book a guide to fully detail this mellifluous marriage of Moghul, Moorish and Arab architecture.