Shamballa, the ancient home of Sanat Kumara is located in the etheric realm over the Gobi desert in China. The retreat once physical, has since been withdrawn to the etheric octave, or heaven-world.
Shamballa was originally built for Sanat Kumara, hierarch of Venus, who long ago came to Earth in her darkest hour, when all light had gone out in her inhabitants and there was not a single individual on the planet who maintained contact with the God Presence and the Inner Buddha.
This city was originally a physical replica of the Venusian City of the Kumaras and became for all time the legendary Shamballa of the White Island.
The main temple of Shamballa is marked by a golden dome and is surrounded by terraces, flame fountains and seven temples - one for each of the Seven Rays.
The altar of the threefold flame is in the main temple, where the star of Sanat Kumara is hung from the ceiling over the altar. This, the principal focus of the threefold flame upon the planet, was established by Sanat Kumara himself. Through it he connected a ray from his heart to every individual evolving on the planet, and thus he assisted their souls to evolve to the place where they could be taught the laws of self-mastery.
In past ages people would come each year from many miles to witness the visible, physical Sacred Fire and to take home a piece of inextinguishable aflamed wood consacred by Sanat Kumara to light their fires through the coming years. Thus began the tradition of the Yule Log commemorating the return to the fire of Christhood.
For more info there are wonderful messages from Sanat Kumara published as "Pearls of Wisdom" by the Keepers of the Flame Fraternity and by A.D.K. Luk in the "Law of Life" books.
See also

Shamballa is an etheric Retreat. A beautiful 'place prepared' which was actually built here on earth.
At the time, our planet was going through a particularly dark period, with humanity totally unaware of the need to do anything about it. Not one soul carried a flame of consciousness in his heart.

Did God want to save this planet? "Yes"! The Hierarch of Venus stepped forward and offered to 'put his life on the line' to replace the Divine Spark, thus lightening a planet. Yes, he knew it would take "time", but he was willing to try.

The News spread - the move was popular.

One hundred and forty four, thousand souls of light, coming from all directions far and wide, joined Sanat Kumara, the Hierarch.

An 'avant-garde' of four hundred souls came ahead to build on White Island, in the blue Gobi Sea, (where the Gobi desert is today), a replica of the Venusian city of the Kumaras, and they focused one hundred and forty four virtues of the flames of the elements, in the Great Hub.

Shamballa, this White City, was approached by a beautiful marble bridge. The main Temple was marked by a golden dome, and surrounded by terraces, flame fountains, and the seven temples of the rays, situated on a wide avenue lined with trees and flowers, flame fountains and exquisite tropical birds, bluebirds of happiness included.

Sanat Kumara made Shamballa his headquarters and his home. Gautama Buddha was his first initiate and consequently, the one chosen to succeed him when Sanat Kumara returned to his planet, Venus.