China's foreign concessions were territories within China ceded to foreign powers, usually having extraterritoriality - citizens of foreign powers could freely live and trade in them, and they developed their own subcultures distinct from Chinese society.
According to Wikipedia, "some of these concessions eventually had more advanced architecture of each originating culture than most cities back in the countries of the foreign powers origin".
Hankou, one of the three cities which now make up Wuhan, used to have five. The first was the British in 1862, followed by France, Russia, Germany and Japan in 1898. The German one was the first to end in 1917 and the Japanese last following World War 2.
Naturally a walking tour of the area was a must, and several interesting buildings were happened upon.
Here's a shot of the Bund (the road running along the river) c1900 plus a photo taken of the same street today. At time of visit the building on the left which looks like a bank was undergoing refurbishment - a peek inside was briefly possible.
The YMCA appears to still be in use.
This is Hankou's old railway station, DaZhiMen which was the terminus of the Beijing-Hankou Railway, designed by French architects, completed in 1903 and closed in 1991. Was gated at time of visit - not sure of its current use. Postcard is from 1927.
Hankou Orthodox Church on Tianjin Road was built in 1893 and has apparently seen recent major restoration, though there was no access. No date for the postcard.
Finally, a walled-up a building on the Bund. Appears to be a former hotel - though a nearby tourist plaque of the area indicates "Shunfeng Exchange", the characters on the front do spell out 'Long Ocean (something) Hotel'.
Was disappointing not to be able to go in (did ask!) as it's derelict and has some beautiful Streamline Moderne / Art Deco architectural features.
Overall, a brilliant place to go for a wander - only saw some of the area so wouldn't mind a revisit!