Tour require to start too early at 4:30am drive out from Siem Reap to Phnom Penh take about 4-5 hours. In Phnom Penh we will go to see:
Royal Palace is a complex of buildings which serves as the royal residence of the King of Cambodia. Its full name in Khmer is the Preah Barom Reacheaveang Chaktomuk Serey Mongkol. The Cambodian monarchs have occupied it since it was built in the 1866s, with a period of absence when the country came into turmoil during and after the reign of the Khmer Rouge.
The palace was constructed between 1866 and 1870, after King Norodom relocated the royal capital from Oudong to Phnom Penh. It was built atop an old citadel called Banteay Keo. It faces approximately East and is situated at the Western bank of the cross division of the Tonle Sap River and the Mekong River called Chaktomuk (an allusion to Brahma).

Wat ‎Choeung Ek Killing Field is the site of a former orchard and mass grave of victims of the Khmer Rouge – killed between 1975 and 1979 – in Dangkao Section, Phnom Penh, Cambodia, about 17 kilometres (11 mi) south of the Phnom Penh city centre. It is the best-known of the sites known as the Killing Fields, where the Khmer Rouge regime executed over one million people between 1975 and 1979. Mass graves containing 8,895 bodies were discovered at Choeung Ek after the fall of the Khmer Rouge regime. Many of the dead were former political prisoners who were kept by the Khmer Rouge in their Tuol Sleng detention center and in other Cambodian detention centers.
Today, Choeung Ek is a memorial, marked by a Buddhist stupa. The stupa has acrylic glass sides and is filled with more than 5,000 human skulls. Some of the lower levels are opened during the day so that the skulls can be seen directly. Many have been shattered or smashed in.

Tuol Sleng Genocide is a museum chronicling the Cambodian genocide. The site is a former secondary school which was used as Security Prison 21 by the Khmer Rouge regime from 1975 until its fall in 1979. From 1976 to 1979, an estimated 20,000 people were imprisoned at Tuol Sleng and it was one of between 150 and 196 torture and execution centers established by the Khmer Rouge and the secret police known as the Santebal (literally “keeper of peace”).

Wat Phnom is a Buddhist temple in Doun Penh, Phnom Penh. It is a pagoda, that symbolizes the name of Phnom Penh, and a historical site that is part of the Khmer national identity. Wat Phnom has a total height of 46 meters (150 ft). The pagoda is named after Lady Penh from the story of the discovery of the five statues: four Buddha statues and one Vishnu statue.

We will finish tour in Phnom Penh around 4:00pm then we will drive back to Siem Reap. When we reach to Siem Reap around 9:00pm.