Gaia is a music group started initially as an alias of Armin van Buuren, which is known for the songs like "Tuvan", "Stellar" and "Empire of Hearts". The current members of Gaia are Armin van Buuren and Benno de Goeij, hence when a Gaia set is performed live, Armin and Benno both take the stage together. Armin has a running joke where he refers to Gaia as 'his friends' in order to not associate himself with the project.
A future Gaia album is in the works as stated by Armin van Buuren in a Q&A session with fans on Facebook.
Due to the nature of an artist alias, the Gaia project is supposedly governed by a certain philosophy.
1. https://www.beatport.com/artist/gaia/41964/tracks?per-page=150
2. https://www.discogs.com/artist/19081-Gaia
3. https://www.facebook.com/arminvanbuuren/videos/10153829427413316/