The Land of Light (also known as Planet Ultra) is the homeworld of the Ultramen, located in Nebula M78. The Land of Light is a clear planet, with somewhat clear green colored buildings. The matter of the planet is made of crystal, and can be broken with a strong hit.
The Planet is itself composed of floating, huge lands, circling it's center, similar to a galaxy, in the center there is a very strong light that lights up the entire planet, which is where the Plasma Spark is located and where the Ultras receive their energies from.
Related Post : Source : ultra-wikia