 The city's layout is similar to that of an amphitheatre; commercial districts are near the water, while residential neighborhoods are located on the hills above.Its population is difficult to ascertain due to the rapid growth of slums in the hillsides above the city; however, recent estimates place the metropolitan area's population at around 3.7 million, nearly half of the country's national population.The city was catastrophically affected by a devastating earthquake in 2010, with large numbers of structures damaged or destroyed.