Southern of Northeast is the old source of civilization in Southeast Asia. This is the route of Khmer civilization who had been live there before. Start from Bangkok through Nakhon Ratchasima, Buriram, Surin, Sisaket and Ubon Ratchathani, The gateway to Southern of Laos.
Nakhon Ratchasima has a lot of interested tourist attraction of history let start from pray respect to Thao Suranari Monument and go to the biggest stone castle of Thailand, Phimai historical park. They believe this is role model of Angkor wat. Next from Phimai historical park is Phimai National Museum and Big Banyan which older than 350 years
This is the land of stone castle such as Phanom Rung Stone Castle, Mueng Tum Stone castles, Nhong hong Stone castles. The main stone castle is the beautiful pink stone castles and carved images of Buddha and tales of religion.
Let go to visit Sikhoraphum temple. The only Khmer castle that has Carving images of Apsara and the beautiful and complete carving stone images of Shiva nataraj in Thailand.
Sisaket is full of Old Khmer civilization. The main tourist attractions are Khao Phra Wihan National Park and the beautiful view point Pha Mor E Daeng which had Template of bas-relief in Preah Vihear Temple.
This is the gateway to Southern of Laos. Start from Sam Pan Boak, Ancient painting older more than 3,500 years at Pha Tam National Park and Go to see beautiful nature and view point of Mea Kong river at Pha Dong Na Tam Forest in September - November are season of wild flowers.