Bangkok is attempting to challenge its reputation as one of the world's most congested cities with the opening of a new subway system.
King Adulydej and Queen Sikrit at the subway opening ceremony
On Saturday, Thailand's King Bhumibol Adulydej opened the first part of the network which officials hope will cut traffic by 50%.
It is also hoped the Metro will cut pollution in the city.
The trains are expected to carry up to 100,000 people an hour through Bangkok's most densely populated areas.
Building the line has been an engineering feat, with tunnels cut deep into hard clay to avoid the waterlogged soil.
Station entrances jut 90cm (three feet) above the pavement to prevent the annual flood waters streaming in.
The line, built by a public-private partnership, will run 20 kilometres (12 miles) through the city.
The $2.5bn route is the first of four planned routes, which officials hope will form part of an integrated transport network in the city.
Taxi drivers have complained that the new network will harm their business.