Very interesting .. Romania in the early and mid 20th century was Europe's largest oil producer excluding the Soviet Union. Constanta if I recall is Romania's center of oil production it's cool to see what i'm assuming are effects of the "oil boom". I've also heard that Bucharest was one of the most cosmopolitan cities in central or eastern Europe during the interwar years unfortunately Nicolae Ceaușescu fancied himself an urban planner and knocked down 1/4 of the old city to make way for the 2nd largest administration building in the world (planned to be the largest but the revolution of 1989 halted construction).
Palace of the Parliament
https://en.wikipedia.org/wiki/Palace..._Bucharest.jpg