Further on, it flows about 100 m below the city, forming two underground lakes connected by a siphon. During heavy rains, the siphon cannot hold all the incoming water, in which case a lake up to 2 km long forms in the Fojba Cave. The lake forms extremely rarely; it was observed in 1883, 1896, 1930, 1935, 1961, 1964, 1974, 1993, and most recently in 2002.
