Earth Opera - album - was created in 1968.
There Are Giants in the Earth was created on 2004-10-26.
Once Giants Roamed the Earth was created in 2005.
The Flying Opera was created in 2008.
Pacific Opera was created in 2003.
The Threepenny Opera was created in 1928.
Martha - opera - was created in 1847.
One - opera - was created in 2003.
Gilgamesh - opera - was created in 1986.
Pauline - opera - was created in 1876.
Fosca - opera - was created in 1873.
The Saracen - opera - was created in 1899.