To accommodate the growing commerce at Honolulu Harbor, from 1856 to 1860, the work of filling in the reef to create an area known as the “Esplanade” (where Aloha Tower is now situated) was underway. They removed Fort Kekuanohu (Fort Honolulu – then serving as a prison) and used the material “in the construction of prisons, and the filling up of the reef.”
On the ʻEwa side of Nuʻuanu stream was a fishpond. The new prison was built on a marshy no-man’s land almost completely cut off from the main island by two immense fishponds. The causeway road led to the new “Oʻahu Prison,” simply called “The Reef;” it was a coral block fortress built upon coral fill at the end of a coral built road over the coral reefs and mudflats of Iwilei.