Spend a lovely half day out of city to Oudong Mountain where located about 40 kilometers northwest of the modern capital Phnom Penh. Oudong was Royal Residence and Cambodia's capital for more than 250 years until 1866. The transfer takes time about 1 hour per way. Arrive at the bottom part, start claim up on stairs uphill to the ridge, a memorial to the victims of Khmer Rouge and still has bones which collected from mass graves. At the top of mountain has a modern temple that contains many Buddha statues and the most impressive is the remains of Arthaross temple, a massive enclosure housing a big Buddha. Wander around to admire the historic temple as well as mountain views to look over jungle and countryside before returning back to your hotel in Phnom Penh.