Khao Phra Wihan National Park

Khao Phra Wihan ('Preah Vihear' in Khmer) is a large Khmer temple ruin perched dramatically on a cliff 500m above the plains below. It's just over the border in Cambodian territory and currently not accessible from the Thai side due to a border dispute. All that is open to visitors now are scenic overlooks and some minor Khmer ruins, all of which are interesting, but not really worth the 400B admission fee.