Based on the Highest High Tide levels recorded of 27.05 metres, a Datum line was fixed on the Town Hall steps (now the Asiatic Society and State Central Library) - a mark (a circle with a dot in the center carved out on the side of the lowermost stone step and painted in red colour) which is visible even today - the minimum plinth levels of buildings was fixed at 28 metres which means that all buildings had their ground floor levels above 28 metres so that even in the worst case the flood waters would not enter the houses.
Known as the Asiatic Society Building, this striking Neoclassical edifice was completed in 1833. The 1804 date on the façade refers to the formation of the Asiatic Society whose library is now housed in this building. It was designed by Thomas Cowper as the Town Hall of Bombay, a library and a museum. Its placement up a flight of 30 steps gives the building the appearance of a Greek acropolis. It overlooks Horniman Circle (formerly Elphinstone Circle).
The Town Hall overlooks the Horniman Circle in the business district of the city of Mumbai. It was built in 1830 in Greek and Roman style and features a portico with eight Doric columns and a flight of 30 steps leading up to its entrance. It is considered to be among the finest Neo-Classical buildings in India. The building houses the Asiatic Society of Mumbai which includes a library which is home to over 100,000 books including one of only two known original copies of Dantes Divine Comedy that dates from the 14th century and over 3,000 ancient manuscripts in Persian, Sanskrit and Prakit.
With its old parquet floors, spiral staircases, wrought iron loggias, and exquisite marble statues of forgotten city fathers, the colonnaded Town Hall is perhaps the most regal and elegant of Mumbai's heritage buildings. It houses the Asiatic Society, a library with a collection of 800,000 antique volumes. One of them is a priceless first edition copy of Dante's 'Inferno.' There is also an impressive numismatic collection of over 1,000 ancient coins and a rare gold mohur belonging to the Mughal Emperor Akbar. You need permission to look at these treasures, but the public library is open to all and usually draws a large number of senior citizens who pore over the local newspapers in the fading grandeur of its reading room.