The Sanmarus Institute was a deep space research station. It was located in the void between galaxies because, according to the Eighth Doctor, some of its research was "positively apocalyptic".
The Doctor visited the Institute with Charley Pollard and C'rizz during Zalaron's time as director of the Institute. A space-time navigator was kept at the Institute. The Collective was located at the Institute. (PROSE: Before Midnight)