Charoen Krung Road (Thai: ถนนเจริญกรุง, pronounced [tʰā.nǒn t͡ɕā.rɤ̄ːn krūŋ]) is a major road in Bangkok and the first in Thailand to be built using modern construction methods. Built during 1862–1864 in the reign of King Mongkut (Rama IV), it runs from the old city centre in Rattanakosin Island, passes through Bangkok's Chinatown, continues into Bang Rak district, where it formerly served the community of European expatriates, and ends in Bang Kho Laem. Construction of the road marked a major change in Bangkok's urban development, with the major mode of transport shifting from water to land. Charoen Krung Road was Bangkok's main street up to the early 20th century, but later declined in prominence. It is still home to many historic buildings and neighbourhoods, which are beset by changes as extension of the underground MRT is poised to drive new development.