Delirium Archive

The Delerium Archive is a museum which takes up most or all of an asteroid, and was the final resting place of the Headless Monks. It was stated by the Eleventh Doctor to be "the biggest museum ever". It is implied he visits often, and uses it to "keep score", however, he may be referring to museums in general, of which this is just one of the places he frequents.

River Song deduced that eventually, the Doctor would at some point end up at the Delerium Archive and find the Home Box of the Category 4 Starliner "Byzantium", thus she was able to leave a graffiti message on it alerting him to her needing his help. She did not know, however, that the Byzantium would crash. He eventually did, roughly 12,000 years after the 51st Century. (DW: The Time of Angels)