Phnom Krom rises south of Siem Reap near Tonle Sap, with a small Angkor-era temple on the summit and broad views over fields, villages, and the lake. It is a good counterpoint to the forested temple circuits north of town because the landscape opens out around you.
The climb is part of the visit, and sunset is the obvious time if the weather is clear. The temple itself is weathered and relatively simple, but the combination of archaeology, hill, and lake horizon makes Phnom Krom worth the detour.