In 1942 the US military needed to send low-frequency signals so that they could communicate with their submarines circling Japan. They needed a radio transceiver and they needed it to be really high, so the peak of Puʻukeahiakahoe mountain in Hawaii was chosen. A somewhat wobbly wooden pathway was made and the transceiver and its antenna cables were installed. The pathway is still there today, but is out of bounds to those who wish to climb this Stairway to Heaven as it has become known.