Kurukshetra is known as Samanta Panchaka (meaning “five lakes”) because here Lord Parashurama made five lakes from the blood of kshatriyas he killed. (Lord Parashurama purged the earth of wicked kings and warriors twenty-one times.) Srila Prabhupada said that the blood later turned into water.
One of these 5 lakes is called Sannihit (“assembly”). On the new-moon day all the holy places personified are said to assemble in the lake. At the time of a solar eclipse, pilgrims take bath in Sannihit Lake, known as an abode of Lord Vishnu.