The Molten or Brazen sea used in the Hebrew temple was enormous. They used it to cleanse themselves while working at the temple (very simplified description, I know.) It also represents a flat earth. I found an entry in Hebrew commentary that described the Molten Sea thus:
J. Jr. I. M. P.—In Rabbinical Literature:
The layer contained water sufficient for 150 ritual baths ("miḳwaot"), if forty seahs be taken as the legal measureof such bath. The laver was not entirely round, as might be inferred from Scripture (I Kings vii. 23): the upper two-fifths were round; but the lower three were square ('Er. 14a, b). The symbolism of the brazen sea is described in detail in the Midrash Tadshe. The sea represented the world; the ten ells of diameter corresponded to the ten Sefirot; and it was round at the top (according to the Talmud passage above cited) as the heavens are round. The depth of the sea was five ells, corresponding to the distance of five hundred years' journey between heaven and earth (compare Ḥag. 13a). The band of thirty ells around it corresponded to the Ten Commandments, to the ten words of God at the creation of the world, and to the ten Sefirot: for the world can exist only when the Ten Commandments are observed; and the ten Sefirot as well as the ten words of God were the instruments of the Creation. The two rows of colocynths (knops) below the rim were symbolic of the sun and the moon, while the twelve oxen on which the sea rested represented the zodiac ("mazzalot"). It contained 2,000 baths (cubic measures), for the world will sustain him who keeps the Torah, which was created 2,000 years before the world (Midrash Tadshe ii., ed. Epstein, in "Mi-Ḳadmoniyot ha-Yehudim," xvi., xvii.; Yalḳ., Kings, 185).
This is very interesting, thanks for this.
Just wanted to add a note: all mormon temples have a replica of this brasen sea where they perform secret rituals such as baptisms for the dead.