Porthcurno Telegraph Station dates from 1870 when an undersea cable from Portugal terminated on the beach. It provided the final link in a chain that stretched all the way to Bombay (now Mumbai) in India. Porthcurno was chosen over other sites due to its relatively sheltered site. By 1929 a total of fourteen cables terminated at the site, making it a vital link to the British Empire. The company operating the site became known as Cable and Wireless.
During World War II the importance and vulnerability of the telegraph station was recognised and a protected underground site was blasted out of the granite rocks. Edward Nuttall were the contractors and the facility opened in 1941. The underground site comprises two parallel tunnels, each 150 feet in length. Original artifacts and period exhibits are still within the tunnels which are listed at Grade II*. At the end of the tunnels 120 steps lead up to emergency exit from outside of which there are excellent views.
Today the site operates as a museum known as PK Porthcurno (PK being the telegraphic code for the station).