When World War II broke out in 1939 and Holland was occupied in May 1940, the need to defend the overseas territories of the Dutch Kingdom in the Caribbean was felt. At Juwana Morto a coastal battery was built in August of 1940 to protect the Lago oil refinery from German attacks.

The battery consisted of a bunker serving as command post and three gun emplacements, all in a line, about 50 meters from each other. The ruins can still be found around Weg Kustbatterij in San Nicolas.

The command post bunker is easy to be spotted from Diamantbergweg. On the top floor, there was a narrow opening in the walls to allow viewing of the area, overlooking the refinery, and to fire if needed. On the ground floor there was the control room and another room for the switchboard. On the north side, a concrete flight of stairs led to the roof above the control room.

Each of the three gun positions stood on steel and concrete foundations. Each was mounted by a 19.2 caliber cannon which could rotate 360 degrees, with a range of 18.5 kilometers. Oranjestad and its harbor were within range as well. The cannons were named Betsy, Jopie and Beppie by the soldiers, members of the Aruba Volunteer Army.

The Juwana Morto coastal battery never fired a shot to defend the area, not even when San Nicolas harbor and Lago Refinery were attacked by a German U-boat in February of 1942. Lake tankers were set ablaze, causing smoke and fire to obstruct the view from the command post.

The ruins of the gun positions are still to be found, for those who can find their way through the harsh cunucu vegetation. The command post bunker, a protected monument, figuring on the list of the Monuments Register, is easily accessible.

In addition to the Dutch-built coastal defense battery on Juana Morto, the Americans built a gun emplacement on the Sero Colorado hilltop with cannons with a range of more than 25 kilometers.

The Juwana Morto/Sero Colorado coastal battery is the island’s most important military heritage.