Although Phnom Penh is suffering from a bit of urban sprawl, most of the sights of the city are within easy walking distance. You can cover the area between Wat Phnom and the Independence Monument in a comfortable one day stroll, taking in all the sights in between.
Most of Phnom Penh's major sights are along the pleasant Tonle Riverside. In a large traffic circle north of the city center is Wat Phnom, which sits on a hill that gave the city its name. The temple had its beginnings in the fourteenth century, but has been rebuilt so many times that nothing remains of the original shrine. At the center of the city near the river is the Royal Palace, which also holds the magnificent Silver Pagoda. Next to the Royal Palace is the beautiful National Museum. A bit south of the Palace is the Independence Monument.