Please give me a short bulleted list of the most important facts about the album “The Dark Side of the Moon” from the rockband Pink Floyd

- published on March 1, 1973
- recorded at Abbey Road Studios in London assisted by unknown sound engineer Alan Parsons 
- Pink Floyd used innovative technologies such as multitrack recording and analog synthesisers
- the album explores themes such as time, death and mental illness
- as of 2013 Pink Floyd sold more than 45 million copies of “The Dark Side of the Moon"
- the album was the 4th best selling album of all time
- it was charted in the US charts for 977 weeks 
- it was selected for preservation in the US National Recording Registry by the Library of Congress as "culturally, historically, or aesthetically significant"