The Altenbeken Viaduct (inaugurated 21 July 1853 by King Frederick William IV of Prussia) is a 482 metres (1,581 ft) long and up to 35 metres (115 ft) high double track limestone railway viaduct. It spans the Beke valley, west of the town of Altenbeken, in the Land of North Rhine-Westphalia, Germany.

The viaduct is Europe's longest limestone bridge, and its construction was one of the earliest significant events in the history of rail transport in Germany. As part of the Hamm–Warburg railway between Paderborn and Altenbeken, it is still in use today. (Source: Wikipedia)