LIMA, PERU (AP).- Tourists love the enigmatic Inca citadel of Machu Picchu high in Peru’s Andes. They may love it too much. As the country prepares to celebrate the 100th anniversary of the rediscovery of the “Lost City of the Incas” on Thursday, archaeologists are warning that a heavy flow of visitors and poor administration are threatening one of the wonders of the world. The Incas built Machu Picchu atop an Andean peak 7,970 feet (2,430 meters) high, with a breathtaking view across the inhospitable abysses that surround it. Some experts believe it was a refuge for one or more Inca rulers, others that it was a religious sanctuary. The site receives an average of 1,800 visitors a day and the maximum allowed by authorities is 2,500. Already, the former farming village of Aguas Calientes that is used as a jumping-off point for tourists has grown into a town of 4,000 inhabitants with five-star hotels and restaurants. In some places, authorities have noticed soil erosion and damage