Arecibo is one of the best cities in Puerto Rico, known for its unique adventures and water sports. It is also blessed with hidden caves, rivers, limestone formations and the best mountain treks in Arecibo. The Arecibo Observatory is one of the famous astronomical observatories in Puerto Rico for a guided tour. The Arecibo Lighthouse and Historical Park are also some of the major attractions in Arecibo that attract many tourists each year.