via Bangkok Post, 25 August 2018:

A cannon believed to be around 200 years old has been uncovered in the middle of Sanam Luang in Bangkok.
Thai media reported the cannon might have dated back to the reign of King Rama II (1809 to 1824). It is 3.05m long with a 40cm muzzle.
It was found on Saturday evening while workers were laying drainage pipes as part of the renovation of the ceremonial ground. They found it at the depth of 1.5m and used a backhoe to lift it out. All parts were intact except for the missing carriage.
Source: Ancient cannon found at Sanam Luang | Bangkok Post: news
See also: