The Western City Gate — universally known as the Genex Tower after the Yugoslav trading company that originally occupied it — is the most architecturally significant building in Novi Beograd and one of the great brutalist monuments of socialist Yugoslavia. Completed in 1977, it consists of two towers of different heights connected by a residential block and topped by a rotating restaurant (currently non-functional) that still defines the Belgrade skyline when approaching from the west.
The tower was designed as a gateway — visitors arriving from the airport would see it first and understand they were entering the capital of a serious, modern country. Whether it succeeds on those terms is a matter of taste, but it is impossible to ignore. The views from the upper floors are superb. The building is partly residential and partly commercial; you can walk up to the entrance and look around the lobby. To see it best, stand across the Sava river from the old city and look west — it rises above everything.