Strait of Gibraltar Tunnel

The Strait of Gibraltar tunnel (Spanish: Túnel del estrecho de Gibraltar, Arabic: نفق جبل طارق) is a proposed rail tunnel spanning the Strait of Gibraltar that would connect Europe and Africa. If built, the tunnel would possibly be the longest railway tunnel in the world, surpassing the Gotthard Base Tunnel and the under-construction Mont d'Ambin Base Tunnel, as well as the longest undersea tunnel, surpassing the Seikan Tunnel.

Source: Wikipedia — Strait of Gibraltar Tunnel (CC BY-SA 4.0)