Bayamón was founded in 1772 by Mario A. Rodríguez León, as a small settlement with an economy based on agriculture. Nearly two centuries later it has become the largest city suburb of the capital metropolitan area and the second most populated municipality of Puerto Rico after San Juan. Commerce, services and manufacturing are the most important revenue areas for the city. High-rise buildings are not as common as in the capital city due to the segregation of population in housing complexes and low-rise buildings known as walk-ups. The walk-up concept, which include structures up to 4 stories high without the necessity of incorporating elevators, has been highly developed in the past decade as an alternative to the growing population and the decreasing amount of land available for construction. This measure results in a less expensive way to solve the problem than the incorporation of high-rise buildings in a zone where the cost of land is cheaper than in the capital city. This concept has been also highly introduced in other metropolitan municipalities such as Guaynabo, Carolina and Trujillo Alto.