Martinstor, Medieval city gate in Freiburg im Breisgau, Germany.

Martinstor is a white-plastered stone tower with reddish-brown trim at its corners and openings, topped by a steep pale green copper spire flanked by two smaller green-roofed turrets. A round clock with gold numerals sits mid-height on the front face, with louvered openings near the top. Its base measures 10 by 11 metres, and the south wall is 3.10 m thick at ground level.

Dendrochronology dates its wooden beams to 1202, and it was first documented in 1238 as Porta Sancti Martini. It later served as a prison, whose inmates were said to have donned the Cloak of Martin. In 1901 Carl Schäfer raised the tower from 22 to 60 metres and added a 15th-century-style roof; a second arch was built beside it.

The gate's name comes from its medieval name Porta Sancti Martini, and from the 17th century a painted image of St Martin of Tours faced the city; the last version, by Wilhelm Dürr in 1851, was removed in 1968/69 and the space remains blank. Beside the arch, a tablet names Marghareta Mößmer, Catharina Stadelmann and Anna Wolffart, executed in 1599.

The gate sits on Freiburg's main shopping street and is open to foot traffic throughout the day as a pedestrian walkway. Be aware that vehicles also pass through the archway and the area gets crowded during peak shopping hours with both visitors and residents.

The McDonald's occupies the 1901 gate building added west of the medieval tower, not the tower itself. Freiburg's city council blocked the chain's red-and-yellow logo above the archway and accepted only a neutral sign. The Martinsgässle beside the arch holds the Markthalle, the Theater am Martinstor and Martinsbräu.