The Roman Bridge in Trier ist the oldest bridge in Germany. The stone pilings of the Roman Bridge date from A.D. 144-152.
The pilings of the Roman Bridge from A.D. 144-152 (the arches and roadway are from the 18th century) are deeply embedded in the bedrock underneath the river gravel.
They were built with huge stone blocks held together with iron clamps as in the Porta Nigra (the Roman clamps are invisible inside the pilings; the visible clamps are from later times). This time, the black color is genuine: the stone is mostly basalt from the Eifel mountains.
On March 2, 1945, General Patton's tanks captured the bridge so quickly that it was not blown up - the (empty) charge chambers are still visible from the up-river side of the bridge.
Further information: trier-info.de/english/roman-bridge-info