Angkor Archaeological Park
Located in northern Cambodia, is one of the most important archaeological sites in Southeast Asia. Stretching over some 400 square kilometers, including forested area, Angkor Archaeological Park contains the magnificent remains of several capitals of the Khmer Empire of the 9th to the 15th centuries, including the largest pre-industrial city in the world. The most famous are the Temple of Angkor Wat and, at Angkor Thom, the Bayon Temple with its countless sculptural decorations.

Angkor Archaeological Park was declared a UNESCO World Heritage site in 1992. At the same time, it was also placed on the List of World Heritage in Danger due to looting, a declining water table, and unsustainable tourism. UNESCO has now set up a wide-ranging programme to safeguard this symbolic site and its surroundings.
Angkor itself has no accommodations and few facilities; the nearby town of Siem Reap is the tourist hub for the area.

Angkor Wat
Located six kilometers north of Siem Reap, Angkor Wat is one of the largest of Khmer monuments. Built around the first half of 12th century by King Suryavarman II, the temple's balance, composition and beauty make it one of the finest monuments in the world.

Though 'Wat' is the Khmer (Cambodian) word for temple, the westward orientation of the structure is atypical of temples. Scholars believe that the architecture and sculptures are that of a temple where Lord Vishnu was worshipped but it was also built as a mausoleum for the king after his death.
The size of the monuments makes it look overwhelming when one encounters it for the first time. The following is one of the suggested plan to explore Angkor Wat. Enter through the west entrance. When you reach the entry tower, walk to the right to get a glimpse of all the five towering gopuras.

Passing the tower and the libraries on both sides of the walkway, climb down the steps towards the left side and get to the water basin. You can catch a glimpse of the temple and its reflection in the water. Go past the basin and reach the left end of the temple.

You would by now have reached the starting point of the famous bas reliefs depicting scenes from various mythological stories and historic events. Walking from left to right you will come across scenes from battle of Ramayana, battle of Mahabharata, army of Suryavarman II, scenes from judgement by Yama (the supreme judge), churning of ocean by demons and gods to get Amrita — the nectar of immortality, Vishnu's victory over demons, victory of Krishna over Bana and other scenes of battle between gods and demons.

Climb the steps to reach the second tier. One can reach the third tier and the central courtyard within by climbing the steps oriented towards any of the four cardinal points. However, it is suggested that the steps on the south (right) be taken, as these have now been fitted with a handrail — particularly useful when descending.

Bayon
Built in the latter part of the 12th century by King Jayavarman VII, Bayon is one of the most widely recognised temples in Siem Reap because of the giant stone faces that adorn the towers of Bayon. There are 54 towers of four faces each, totaling 216 faces. There is still a debate as to who is being depicted in the faces. It could be Avalokiteshvara, Mahayana Buddhism's compassionate Bodhisattva, or perhaps a combination of King Jayavarman VII and Buddha.
Bayon's plan can be divided into three levels — the first two are bas-reliefs and the uppermost consists of the central sanctuary. The outer gallery depicts scenes from everyday life and historical events, while the second inner gallery depicts mythical figures and stories. In total, there are more than 1km of bas-reliefs to be viewed in the Bayon.

Enter Bayon from the east. The outer gallery comes into view first. The second gallery is on the next higher level. The third level is where you will encounter many of the famous faces (and tourists). The fact that these stones are exposed to direct light makes it easy to shoot pictures throughout the day, though mid-day sun eliminates shadows. You will find fewer tourists too during this time of day. Elephants are also available to take you from the gate into Bayon for $10 per person (seats are limited and often already pre-booked by the tour groups, but still worth checking out!)

Other Angkor Thom sights
The Bayon and Baphuon temples form only part of what was formerly the giant city of Angkor Thom, once thought to hold a population of one million.
In addition to the Bayon and Baphuon temples, the ancient city of Angkor Thom holds a number of other sites of interest:
    * The Elephant Terrace.
    * The Terrace of the Leper King.
    * Five entrance gates, one at each ordinal compass point and the Victory Gate in the east wall. The western and the northern gate are free from tourists, and climatic. Each of the gates is topped by the face of Avalokitesvara. There is a path on top of the walls, and one along the outside wall, that can be followed to walk from gate to gate. The total walk is around 13km, about 3.5 hours long.
    * Phnom Bakheng. The first temple-mountain constructed in Angkor, with a commanding hilltop location. Extremely popular (and crowded) spot for sunsets: allow half an hour for the sweaty hike to the top, and leave early or bring a flashlight for the way back. The final climb to the top of the temple is steep and dangerous at dark. Elephants will carry you to the hilltop for $20 per person (as of 2008-11-08), but you still have to climb the temple stairs on your own. Note that the sun does not set over Angkor if seen from here, and any visible temples are in fact quite far away. Also note that you are NOT allowed to climb Phnom Bakheng after 17.30 - hence make sure you arrive earlier. An elephant ride back down the hill will cost $15.

Little Circuit
In clockwise order, exiting Angkor Thom by the Victory Gate:
    * Ta Keo. An incomplete, largely undecorated temple built by Jayavarman V. The stairs at the east side of the monument are least steep and the easiest way to reach the top level.
The famous empty doorway of Ta Prohm — there's usually a queue of people lining up to be photographed here!
    * Ta Prohm. Built during the time of king Jayavarman VII and is best known as the temple where trees have been left intertwined with the stonework, much as it was uncovered from the jungle. It might be considered in a state of disrepair but there is a strange beauty in the marvelous strangler fig trees which provide a stunning display of the embrace between nature and the human handiwork. This is one of the most popular temples after Angkor Wat and the Bayon because of the beautiful combinations of wood and stone. Black and white film photographers especially love this site because of this and most of the stunning postcard shots of Angkor's trees come from here; pop culture fans, on the other hand, may recognize a few scenes from Angelina Jolie's Tomb Raider. While the temple is very popular, most visitors follow a central route and the sides of the complex can be surprisingly quiet. Note that large sections of the temple are unstable rubble and have been cordoned off, as they are in real danger of collapse. As of 2010, authorities have started to restore Ta Prohm. All the plants and shrubs have been cleared from the site and some of trees are also getting removed. A crane has been erected and a large amount of building work is underway to rebuild the temple, much of it seemingly from scratch. Wooden walkways now block some of the previously famous postcard photos.
    * Banteay Kdei. Sprawling monastic complex in the style of Ta Prohm. In poor shape, but slowly being restored.
    * Sras Srang. Terrace leading to a pond. Located right across the road from Banteay Kdei.
    * Prasat Kravan. A little temple to end the little circuit.

Big Circuit
In clockwise order, exiting Angkor Thom by the North Gate:
    * Preah Khan. Jayavarman VII's first capital, before the completion of Angkor Wat. Large and atmospheric, yet somewhat overshadowed by Angkor Wat and Ta Prohm, this temple is partly in disrepair with strangler figs crawling up the walls, but has some excellent carvings and less visitors, and is well worth a visit. The temple is some 3 kilometers north of Angkor Thom.
    * Neak Pean.
    * Ta Som.
    * East Mebon. Located on what was an island in the now dry East Baray, this is a large, three-story temple-mountain crowned by five towers, like a miniature Angkor Wat. Originally built by Rajendravarman II in the 10th century, many structures are in poor shape, but the temple is best known for its massive (restored) elephant statues.
    * Pre Rup. A temple-mountain close to and quite similar in style to East Mebon, and constructed only a decade later. A favorite spot for viewing the sun set into the jungles and rice paddies of the Cambodian countryside.

Outlying temples
    * Banteay Srey, 37 km north of Angkor Wat. This red colored temple is well known for its intricate carvings, and is worth a half day trip on its own, since it is a bit further from Siem Reap than the main Angkor Thom and Angkor Wat areas. Car and motorcycle drivers will charge a bit extra ($10 USD) to take you to the temple.
    * Kbal Spean. After the man-made monuments of the temples, it can be nice to get back to nature for a while at Kbal Spean. Although it is the site of numerous carvings made into the rock of the river bed and surrounding areas, this lies at the end of a 1.5km (1 mile) walk through some Cambodian rain forest. There is a small but attractive waterfall that drops to a picturesque pool, all surrounded by precariously perched boulders and creeping vines. Drier weather means less water and easier viewing of the carvings. Best combined with a trip out to Banteay Srey, as this is a further 5km or so along a rough road. Expect to pay extra to drivers who take you this far.
    * Beng Mealea, 80 km east of Siem Reap. Along with Ta Phrom and others, this is a temple which has been left to nature, but unlike Ta Phrom only a few trees have been removed. The result is the visitor clambering over ruined walls (exactly the sort of thing you are asked not to do at other ruins!) and through windows to get access to areas where nature is running riot. Lots of trees growing out of walls, and creepers hanging over ruined buildings, and consequently great for some atmospheric photos. Much of the standard walk is along wooden decking for those who don't want to clamber. This can be taken in as part of a trip to the Roluos Group, or a long day trip with Banteay Srey and Kbal Spean, though this will entail about 5 hours travelling in total on some very rough roads. There is a $5 entry fee to Beng Mealea. Though you may want to cast a wary eye toward custodians bearing Äspara Authority armbands and local kids following you in an attempt to extract guide fees, there are, in contrast to other temple sites, almost no vendors here.
    * Phnom Krom, 12 km southwest of Siem Reap. This hilltop temple was built at the end of the 9th century, during the reign of King Yasovarman. The gloomy atmosphere of the temple and the view over the Tonle Sap lake make the climb to the hill worth while. A visit to the site can be conveniently combined with a boat trip to the lake. Obviously, the Angkor passport is needed to enter the temple so do not forget to bring your passport along when heading to Tonle Sap.