The fortifications of Bangkok consist of several series of defensive structures built to protect the city during the late Ayutthaya to early Rattanakosin periods.
As an important outpost guarding the Chao Phraya, Bangkok (then located on the west bank of the river) was protected by city walls.
[2] Taksin was overthrown in 1782, and the new King Phutthayotfa Chulalok (Rama I) reestablished the capital as Rattanakosin, moving the city proper to the river's eastern bank.
To prevent evil spirits entering, it was situated in the direct line of sight of the Emerald Buddha, enshrined on the other side of the city in the royal temple of Wat Phra Kaew.
[6][a] Rama I's fortifications were built to address traditional defence concerns, especially the lingering threat of a Burmese invasion that continued on for several decades.
From south to north, they are:[4] Bangkok underwent rapid modernization beginning in the late 19th century, and by the 1920s most of the city's original forts and walls had been demolished to make way for the construction of roads and buildings.
During the reign of King Prajadhipok (Rama VII, 1925–1935), the Royal Society resolved to preserve the two remaining original forts, Phra Sumen and Mahakan, for their historical value.
The fort has been used ceremonially for the firing of gun salutes since 1979, when Memorial Bridge was permanently lowered, preventing warships from sailing upriver to perform the task.
[11] Near Mahakan Fort, between the city wall and the canal, lies an old community whose wooden houses serve as an example of historic vernacular architecture.
Although agreements had been made in the 2000s to preserve and develop the neighbourhood as a living museum, the deals later broke down, and the BMA began demolishing houses whose owners accepted compensation in 2016.
The gate's 12-metre (39 ft) pointed roof, which had earlier collapsed, was rebuilt in 1981 using photographic evidence from the reign of King Rama V.[4] Pong Patchamit Fort is the only remaining of those built in 1852–1854 to guard Phadung Krung Kasem Canal.
It guarded the river together with the opposite Pit Patchanuek Fort, and fired gun salutes welcoming royal envoys during the time of King Mongkut.
While official requests to scrap the fort for materials were documented as early as 1907, these were initially rejected, and it is unknown when the partial demolition took place.
The site remains under the authority of the Marine Department, while the Khlong San District Office building now occupies part of the fort's former area.