"X-Men" #1, from 1991, is the best-selling comic book of all time, with sales of over 8.1 million copies and nearly $7 million, according to a public proclamation by "Guinness World Records" at the 2010 San Diego Comic-Con. The sales figures were generated in part by publishing the issue with five different variant covers, designated #1A, #1B, #1C, #1D, and #1E. The first four covers show different characters from the book that form a single image when laid side by side, and a fifth, gatefold cover of that combined image, large numbers of which were purchased by retailers, who anticipated fans and speculators who would buy multiple copies in order to acquire a complete collection of the covers.