Lake of Lusor

The Lake of Lusor was a body of water located on Qo'noS, the Klingon homeworld, near the Kri'stak volcano.

According to Klingon religion, after plunging a lock of his hair into lava from the volcano, Kahless the Unforgettable forged the Sword of Kahless, the first bat'leth, by cooling the sword in the Lake of Lusor. 

See von Lusor Lac de Lusor Meer van Lusor