Sana'a is one of the oldest continuously inhabited cities in the world, and its old quarter, a tight maze of tall mud-brick and stone houses, looks almost impossibly intricate. The buildings rise six or seven storeys, their facades decorated with white gypsum patterns around the windows, and the windows themselves are often filled with coloured glass that glows in the evening. The city lies on a high plateau, at about 2,200 metres in the mountains of Yemen, and the air is thin and dry and bright.
Legend gives the founding to Shem, the son of Noah, and the city certainly existed long before Islam arrived. It was an important stop on the incense and spice routes, and under Islam it became a major centre of learning, with dozens of mosques. The Great Mosque is one of the earliest in the world. Inside the old walls are markets, called souks, grouped by trade, selling spices, silverware, coffee and daggers. The city's character comes from the ways in which these buildings were adapted to a crowded, high-altitude world, with rooftop gardens and tall towers called tower houses.
For visitors, the biggest issue is safety. Yemen has been in a state of conflict since 2014, and travel advice from most governments warns against going, so this is a place to read about, and visit only when the situation allows. The old city is on UNESCO's list of sites in danger, damaged by airstrikes and neglect.
If travel were feasible, the road to Ma'rib across the desert plateau would take you to the ruins of an ancient dam, said to be linked to the legendary kingdom of Sheba, and the mountain roads are spectacular. The capital has fuel and food, and in peacetime the cafes serve strong coffee flavoured with ginger and honey, along with flatbread, lamb and a stew called saltah. Please check official guidance carefully and never plan a ride here on the basis of old information.