Ear to the Heavens' is how it is referred to as by the science fraternity. It is the world's largest radio telescope and also the most sensitive. It has a gigantic 20 acre antenna built into the ground. It is 167 feet deep and has a diameter of nearly a 1000 feet. Tourists can stand on a platform on the corner of the antenna and admire the awe inspiring site and sight. It is situated in between dense forest which makes the telescope stand out. It is situated in the town named Arecibo which is around 1.5hrs drive away from the capital San Juan. Tours are also organized to the observatory.