Efpalineio Tunnel

The Efpalineio tunnel is a tunnel of 1036m near Pythagoreio of Samos, which was constructed in the 6th century in order to work as an aqueduct.
Its special characteristic is that it was opened simultaneously by both sides of the mountain, this tunnel was double-edged as Hrodotos called it, because of what it was known for.
The two tunnels met almost in the middle with a remarkable accuracy, a very important achievement for those times. A part of the tunnel is open to visitors today.