We started with the vist of the the Royal Palace and the Silver Pagoda located just next to the palace grounds. Once you step inside the compound, passing the high walls, there is silence. The Royal Palace of Cambodia is the royal abode of the King of Cambodia. The compound was the citadel of King Ponhea Yat (1393-1463) and rebuilt to its present state in 1886, when King Norodom (1834-1904) relocated the royal capital from Oudong to Phnom Penh. The buildings with beautiful towering spires are a great example of classic Khmer architecture found in Cambodia today. One of the interesting buildings is The Khemarin Palace, also known as Prasat Khemarin or the "Palace of the Khmer King." This is officially the residence of His Majesty, King Norodom Sihamoni. Vistors can visit the Throne Hall (Preah Tineang Tevea Vinichhay) where coronations and official ceremonies take place, the Temple of the Emerald Buddha (Wat Preah Keo Morakot), Stupas (Chedei), a Royal Dining Hall, the Chan Chhaya Pavilion and a French-style building that was a gift from Napoleon .
Silver Pagoda
On the grounds of the Royal Palace, you should not miss the Silver Pagoda, also known as the Emerald Pagoda to Cambodians.
Originally a wooden structure, the palace was initially constructed in 1892 during the reign of King Norodom, but rebuilt to its present grandeur by King Norodom Sihanouk in 1962. The king spared no effort to make this a true embodiment of brilliant Khmer art. More than 5300 pcs of 1.125 kilo silver tiles are used to cover the floor of the Silver Pagoda, and the silver pieces collectively weigh over six tons,The staircase leading into the pagoda is marble, and inside, two breathtaking representations of the Buddha hold court. The Emerald Buddha is in fact made of Baccarat crystal, and dates back to the 17th century. A small glass case nearby enshrines a sacred Buddha relic brought from Sri Lanka in 1956 by the Venerable Loeva Em of Wat Lanka. However, the second statue of Buddha is the one that catches the eyes of visitors. Its 90 kilo gold body is studded with 2086 diamonds; the largest of which a 25 karats brilliant piece can be found on the Buddha's crown. Cast in 1904 by King Sisowath at the request of his elder brother King Norodom, it represents Maitreya Buddha, the future Buddha.
There are a total of 1650 items on display at the temple. They include cast gold headdresses made especially for the royal dancers, many solid gold Buddha statues in different forms, gifts from royalties and dignitaries from around the world and a myriad of jewels and precious antiques.
Wat Phnom
Wat Phnom is a sanctury which contains the ashes from King Ponhea Yat (1393-1463). This is the symbol of the capital city of Phnom Penh and sets prominently atop an artificial 27 meter hill (or 'Phnom') in the northeastern section of the city. Legend has it that Daun Penh, a wealthy widow, retrieved a large koki tree trunk from the river. She had hoped to use it for a house, but inside a hollow of the trunk, she found four statues of the Buddha. She then ordered for a section of her property to be elevated for a small shrine to be erected to revere the statues. This became a sacred site and people started to settle around the hill; eventually, this became the city it now is. It is here that the city gets its name: ‘Phnom’ means hill in Khmer and ‘Penh’ is of course the name of the lady. 
 Tuol Sleng Genocide Museum 
Tuol Sleng means " Hill of the Poisonous Trees" in Khmer. This horror museum is located between street 113 & street 350, southwest of the Phnom Penh City Center. It was the local high school named "Tuol Svay Prey. The high school consists of 4 main buildings, block A & B with L shape allocation south of the compound, and block C & D being allocated transparent position A & B north of the compound. In 1975 the Khmer Rouge took power under the leadership of Pot Pot, Tuol Svay Prey High School had been transformed into a prison called "S-21" or Security Office 21. S-21 was surrounded with a double wall of corrugated irons, and surmounted by electrified barbed wire. The classrooms on the ground and first floor were pierced and divided into individual cells, and second floor used for mass detention. Most of the victims are peasants, workers, technicians, engineers, doctors, students, Buddhist monks, ministers, Pol Pot cadres, solders of all ranks, the Cambodian Diplomatic corps, and even foreigners.