Qatar was not long in exploiting the new-found wealth from oil concessions, and slum areas were quickly razed to be replaced by more modern buildings. The first formal boys' school was established in Doha in 1952, followed three years later by the establishment of a girls' school. Historically, Doha had been a commercial port of local significance. However, the shallow water of the bay prevented bigger ships from entering the port until the 1970s, when its deep-water port was completed. Further changes followed with extensive land reclamation, which led to the development of the crescent-shaped bay. From the 1950s to 1970s, the population of Doha grew from around 14,000 inhabitants to over 83,000, with foreign immigrants constituting about two-thirds of the overall population.