Helcar was raised by the Valar to house the northern of the Two Lamps, Illuin. It was placed in the north of Middle-earth, and together with the southern lamp Ormal lit up all of Arda. Helcar was destroyed by Melkor, and collapsed. This ruined a great part of Middle-earth, and waters (probably from Belegaer and the eastern ocean) flowed in. Later here was formed the inland Sea of Helcar. The heat of Illuin then melted Helcar, and the meltwater of this tower formed the Sea of Helcar.