After decades of upheaval, Cambodia has emerged as a poor but peaceful nation blessed with great natural beauty, hospitable inhabitants and some of the most awe-inspiring temple architecture in the world. Until recently, travelers most often combined a visit to Angkor with stays in other countries. But it is increasingly possible to regard Cambodia as a destination in its own right. The capital, Phnom Penh, is worthy of a day or two’s exploration. The exceptional river cruise company Aqua Expeditions offers journeys down the Mekong and Tonle Sap rivers. And along a stretch of coastline known as the Cambodian Riviera, an increasing number of upscale resorts provides competition for beach properties on the Thai island of Phuket.