León Viejo is a World Heritage Site in Nicaragua. It was the original location of León. It is the present location of the town of Puerto Momotombo in the Municipality of La Paz Centro of the Department of León. It is administered by the Instituto Nicaragüense de Cultura (Nicaraguan Institute of Culture).León Viejo was founded on June 15, 1524 by the Spanish conquistador, Francisco Hernández de Córdoba, who was decapitated at the town's Plaza Mayor (Main Square) in 1526 by governor Pedrarias Dávila, his Lieutenant.Settled by Spanish colonists, León Viejo originally had a native population of about 15,000 and it is located on the southwestern banks of Lago de Xolotlán or Lago de Managua (Lake Xolotlán or Managua), south of volcano Momotombo. The area suffered frequent volcanic activity, culminating in the earthquakes of 1594 and 1610.The city was not destroyed by the 1610 quake, however due to the damage caused to the infrastructure and the seismic activity, the settlers held a referendum and decided to relocate the city to its present location, about 20 miles to the west. Nevertheless, the old city was gradually buried by the continuous expulsions of ash and volcanic stone coming from Momotombo, and by lake sediments.The ruins of León Viejo were discovered in 1967 and excavations begun the following year revealing that the city had a similar layout to other cities in America at that time, laid out on a grid system with a main square located at its center. León Viejo occupies an approximate area of 800x500 mts2. Around the Plaza Mayor and on the surrounding streets, 16 ruins have been partially restored.The city had three monasteries: ""La Merced"", ""San Pedro"", and ""San Francisco"", which remained active until October, 1559. The ruins of La Merced and San Pedro have been identified, however they have been damaged by natural disasters over the years. In May, 1982 tropical storm Alleta wasted the walls of the city. In October, 1988 Hurricane Joan caused new damages to the ruins, and in October, 1998 Hurricane Mitch affected an estimated 40% of the site, damaging several houses, La Merced convent, and La Fortaleza.León Viejo is the only 16th-century, colonial city in America that has never suffered city-planning alterations during its history. This fact was the main argument in the request to the UNESCO when it was declared a World Heritage Site in 2000.