Groups comparison
Megastructure - 1984 to 2017
Bishop Ring(O'Neill cylinder) - 1992 to 2017
Includes a Bishop Ring, or a place akin to such (e.g. O'Neill cylinder), as a location.
Bishop Ring(O'Neill cylinder) - 1992 to 2017
Includes a Bishop Ring, or a place akin to such (e.g. O'Neill cylinder), as a location.
megastructure
bishopring