Entrances to buildings in Belgrade used to be stages where architects showed their utmost creativity in the interwar period. They were designed to woo potential tentants to buy or rent by making a block of flats look like a private castle, or to impose the serious nature of a company or official building.
Some of my favourites were built while Belgrade modernism (local variant of Art Deco) reigned supreme in 1930s, but there are also more ornate ones, which tried to infuse Belgrade with touches of neo-baroque, Art Nouveau or romanticism.
Some, indeed have proper artworks inside, with majestic murals and even inlaid paintings (not to mention wonderfully carved wooden details and doors).
Although most post-WWII buildings were primarily functionalist with little regard to ornaments at entrances, some architects managed to enliven them with nice floor patterns or by making them dramatic.
I never miss an opportunity to take a peek inside and it’s good to see that more and more of entrance corridors are getting restored to their former glory (but still sadly, many doors have been exchanged for cheaper variants).