The Altpörtel — literally "old gate" — is the western anchor of Speyer's medieval fortifications, and one of the most complete city gates surviving in Germany. Built in the 13th century and standing 55 metres tall, it dominated the approach to the city along the Maximilianstrasse, Speyer's long central axis that still runs straight from the gate to the cathedral. The masonry is solid and largely original, with a pointed arch at street level and progressively smaller openings rising to the top. The clock on the facade is from 1761 and still works.
You can climb to the top, and it is worth doing. The view takes in the full length of the Maximilianstrasse below — a satisfying piece of medieval town planning, with the cathedral towers visible at the far end — and extends over the surrounding rooflines to the Rhine plain. The climb is steep and the stairs narrow, as you would expect from a medieval tower, but there is nothing technically difficult about it. Inside, the different construction phases are visible in the stonework, and there are displays about the gate's history and its role in the original city wall circuit.