The pool is in the Throne Room of the Lion Temple. It is where Lion Elders collect orbs of Chi to distribute to the tribes of Chima. It is large and filled with Chi water and has special minerals that cause the Chi orbs to form.
The pool was first formed at the bottom of Mount Cavora after it rose from the heart of Chima. The Lion Tribe was the first tribe to drink from it, so they had the responsibility of guarding it and distributing Chi to all the tribes later on. The Lions' Temple was soon built around it and the Lions collected Chi and Golden Chi from the pool.
The pool remained the source of life in Chima for thousands of years, but when the Black Cloud came and blocked the falls of Chi, it became a dry basin. Luckily, the falls were re-started by the Legend Beasts and distributions of Chi began again.