Ancient temples, BBQ chicken and Waterfalls
The southern part of North-East Thailand, also called the Isan (also written as Isaan or Isarn) is one of my favourite area's of traveling in Thailand. Off the beaten track with ancient history from the Greater Khmer Kingdom and stunning National Parks like Khao Yai in the Sankamphaeng Mountain range as border between the Khorat Plateau and the lower plains of Central Thailand. Khao Yai National Park is one of the biggest and oldest National Parks of Thailand with a beautiful jungle, many waterfalls and wild life like elephants, bears and birds. Khao Yai is also the origin of the Mun River (Moon River) that flows all the way thru the Khorat basin along Khorat (Nakhon Ratchasima), Buriram, Surin, Si Saket and Ubon Ratchathani.
Traveling further into the southern part of North-East Thailand you are entering the area of the Phnom Dangrek Mountain range as border between Thailand and Cambodia. Along this mountain range are many remains of magnificent architecture build along the ancient Dharmasala route from Ankor Wat (Cambodia) to Phimai (Thailand). Near Khorat is "Prasat Phi Mai" and near Buriram is "Prasat Phanom Rung" build on the top of an old volcano. But this area is littered with dozens of small and bigger ancient temples. And near Ubon Ratchathani is just over the border in Cambodia the world famous Phreah Vihar where you can also find pre-historic rock paintings.
While passing beautiful nature and ancient history there are also some nice places to visit as Khorat, Buriram (with the famous racing track), Surin (with the famous Elephant Village) and Ubon Ratchathani as gate-way to Southern Laos. At the almost most eastern point of this area at Chong Mek, bordering with Laos, you are at the place where the Mun River merges with the mighty Mekong River that will shortly after that disappear into Laos.