Arecibo Observatory

The Arecibo Observatory used to include the largest radio telescope in the world, which measured 305 m (1000 feet) in diameter. It was built in 1963, into a natural sinkhole in the hills around Arecibo. In December 2020, cables supporting the receiver snapped and it came crushing down. It was decided that the telescope would not be rebuilt and the observatory was converted into an educational facility. The telescope's dish will be deconstructed.

The facility is operated by Cornell University and boasts an excellent science and space interactive museum. It sits in a beautiful region, 75 km west of San Juan.