It is the Palace of the Parliament in Bucharest, Romania (some more photos).
As to whether it’s the biggest building in the world, Wikipedia says:
According to the World Records Academy, the Palace is the world’s
largest civilian building, most expensive administrative building, and
heaviest building.
But see also the list of largest buildings in the world where it is only mentioned as the largest parliament building in the world.
Credit:stackoverflow.com‘
5 Mar, 2024
4 Mar, 2024