A letter by British scientist Francis Crick to his 12-year-old son sold for $6 million, including a buyer's premium, at an auction on April 10, 2013. Weeks before Crick and James Watson published their DNA discovery in Nature, Crick described DNA's "beautiful" structure in a seven-page letter. "My dear Michael," the letter starts, "Jim Watson and I have probably made a most important discovery." (BNPS)