There are no monuments, museums, viewpoints or other above-ground sights whatsoever on the islands; however, the beaches are a sight in themselves. White sandy beaches with clear water and flanked by rolling jungle covered hills make the views from the beach spectacular. Coral Bay on the small island is the only beach that provides a sunset, but construction of a new jetty has spoiled most of the view. There are several trails that you can take around the island that offer spectacular viewpoints such as the Lighthouse Towers, which you can also climb up and jump off of into the sea.
With luck you might be able spot some of the islands' wildlife, including huge monitor lizards (almost guaranteed - they are not afraid of humans) and monkeys, not to mention nesting turtles at certain times of year. Arguably the Perhentians' best sights of all are underwater, where you're likely to see reef sharks and sea turtles amongst the corals and tropical fish. The island also has a huge population of cats, most of which are kittens that a lot of the locals and expats take care of.