It is Lazio’s second province population-wise (482,327) throughout 3,239 square kilometers. The area boomed industrially in the 1960s, leading to urban development such as Anagni, Cassino, Alatri and Fiuggi, which is also a very important hot spring center. Unfortunately, such development has caused a very serious problem: pollution. As a result, Liri’s valley has become one of the most polluted areas in central Italy. Natural beauty is still a characteristic of the area, though. Despite the low number of lakes (five – two of which are artificial), they are definitely worth seeing. Particular attention should be paid to Fibreno, Saint John Incarico and Canterno lakes.