Bangkok

Bangkok skyline and Chao Phraya river
photo by flickr user Swami Stream

Bangkok is Thailands capital and the only real metropolis of the country with over 10 million people. Located along Chao Phraya River it is a city of many faces.

Wikitravel says:

Just under 14 degrees north of the Equator, Bangkok is a tropical metropolis that is also one of the most traveller-friendly cities in Asia. A furious assault on the senses, visitors are immediately confronted by the heat, the pollution and the irrepressible smile that accompanies all Thais. Despite the sensationalized international news reports and first impressions, the city is surprisingly safe (except from some petty crimes) and more organized than it initially appears, and full of hidden gems waiting to be discovered. The high relative humidity and warm temperature favor the growth of tropical plants — you’ll find exotic orchids and delicious fruit everywhere. Bougainvillea and frangipani bloom practically everywhere. Thai cuisine is justifiably famous, varied, and affordable. Bangkok for many, represents the quintessential Asian capital. Saffron-robed monks, garish neon signs, graceful Thai architecture, spicy dishes, colourful markets, traffic jams, and the tropical climate come together in a happy coincidence. It is difficult to leave with lukewarm impressions of the city.

Wikipedia says:
The city of Bangkok is the capital, largest urban area and primary city of Thailand. Known in Thai as Krung Thep Maha Nakhon (กรุงเทพมหานคร ) or Krung Thep (Th-Krung Thep.ogg กรุงเทพฯ )) for short, it was a small trading post at the mouth of the Chao Phraya River during the Ayutthaya Kingdom and came to the forefront of Thailand when it was given the status as the capital city in 1768 after the burning of Ayutthaya, the former kingdom seat and capital of the Ayuthaya province. It was also ranked by "Travel and Leisure" as the best city in the world for the year 2008. In the span of over two hundred years, Bangkok has been the political, social and economic center of not only Thailand but for much of South East Asia and Indochina as well. Its influence in the arts, politics, fashion, education and entertainment as well as being a business, financial and cultural center of Asia has given Bangkok the status of a global city. Bangkok is the world's 22nd largest city by population with approximately 8,160,522 registered residents (July 2007), but due to large unregistered influxes of migrants from the North East of Thailand and of many nations across Asia, the population of greater Bangkok is estimated at nearly 15 million people. ... read more