General Post Office, Kolkata

The General Post Office stands at BBD Bag, the old Dalhousie Square, in the busiest part of central Kolkata. It is still a working postal headquarters, but it is also one of the city's most striking colonial buildings, mixing Indo-Saracenic and Neoclassical elements behind a grand facade topped by a large dome.

When Calcutta was the British capital, chosen partly for its access to the sea, the post was the main way of moving news and orders, and the GPO sat at the centre of that network. The building watched many of the political changes of the period, and it is a regular stop on heritage walks through the old business district.

Inside, the Philatelic Bureau keeps up the city's long interest in stamp collecting, which peaked in the 1970s and 1980s. It sells commemorative stamps, first-day covers and other items, and holds exhibitions, workshops and talks for collectors.