What does "the terrace formed a green mountain that seemed to float in the city" mean

It´s a reference to the Hanging Gardens of Babylon.

Explanation:

The Hanging Gardens was an outstanding terrace of trees and plants in Babylon city. Along with the Tower of Babel and the Ishtar Gate, these garden seemingly floating over the city is one of the improvements the king Nebuchadnezzar made to the city, in an attempt to add beauty to a place already deemed as the Gate of God.

for the united states of america, 1945 to 1964 was a time of high economic growth and general prosperity. it was also a time of confrontation as the capitalist united states and its allies politically opposed the soviet union and other communist countries; the cold war had begun.

explanation:

the hollywood film industry of 1950 was threatened on several different fronts. television broadcasting was rapidly becoming the dominant entertainment medium in the united states. the paramount anti-trust consent decree requiring separate ownership for production companies and theater chains had gone into effect on 1 january 1950. large numbers of young men and women were marrying, having children, and moving to the suburbs, which affected the viability of downtown first-run movie theaters. foreign revenues were endangered by protectionist tactics including quota systems, high taxes, and blocked funds. finally, the morality and patriotism of hollywood films and filmmakers were under attack from government, religious, and citizens' groups.

explanation: