The Alcazaba of Mérida is a square fortress beside the Roman bridge over the Guadiana, built in 835 on the orders of the emir Abd al-Rahman II of Córdoba to control the city after local rebellions. What fascinates visitors is how it was built: the Muslim engineers used stone taken from Roman buildings, including inscribed blocks, column bases and fragments of old walls, so the fortress is a collage of earlier centuries. Inside there is a remarkable water cistern, reached by a stairway down toward the river level, where water filtered into a covered tank that shows how carefully the builders thought about water.
The albarrana tower is a type of defensive structure typical of medieval Spanish military architecture: a tower standing slightly apart from the main wall, joined to it by a bridge or a section of wall, so that defenders could shoot at attackers who had reached the main wall. It is a clever, awkward-looking thing, and finding one is always satisfying. Fragments of the Roman city wall also survive in Mérida, and their massive masonry, laid without mortar in places, gives some idea of the scale of the ancient city. Walking around the old centre, you pass from one era to another within a few paces.
Riding into Mérida from the north or east you cross the Guadiana plain on long, straight roads through olive and fig groves, vineyards and wheat fields, with a little traffic and a lot of space. Roads are generally well maintained, and the corners are mild. In the city, the Roman bridge, about 790 metres long, is pedestrian only, and a modern bridge carries the traffic alongside. Parking near the Alcazaba is straightforward in the morning but can be tight at midday, and the streets of the old centre are one-way in places.
The city has all you need, with fuel stations on the main roads and small bars serving tapas and coffee. Calamonte is a short ride away with supermarkets and garages. In the middle of summer the heat can reach forty degrees, and the stone walls reflect it, so visit early or late. The evening light on the river is lovely, and the smell of warm stone and river water is distinctive. Sit on the bank in the dusk and watch the swifts wheel above the old walls.