Original:  The puzzle was designed by William Sunners, a Brooklyn schoolteacher for a fee of $15,000 (roughly 4 years salary in that era). In the 1950s the focus of puzzle contests became fund-raising. Organizations such as the Boy Scouts and the Salvation Army would advertise their contests in large-circulation magazines. These contests either had an entry fee to play, or required a donation to the sponsoring organization. The most popular format for these contests was a picture composed of digits. The player had to correctly add all of the digits. The final tiebreaker would require the player to draw a path through a grid of several hundred numbers to obtain the highest possible total. Modern era The current era of puzzle contests, in which the contests are conducted almost entirely by mail, began in the early 1970s. A promoter of packaged vacation tours called American Holiday Association (AHA) decided to use a puzzle contest to publicize its holiday packages. The puzzle contest proved so popular, that eventually AHA dropped its vacation business and became exclusively a puzzle contest promoter. The best-known of the AHA contests was their BINGO format word grid. In the first round the player had to fill in 5 words into the 5x5 grid, meshing with the word BINGO that had already been filled into the left column. Since there were only 2 words in the word list starting with B, only 2 words with I, etc., no real skill was required. The second round was similar, with BINGO filled in the diagonal. Again, there were only 2 words starting with B, only 2 words with I in the second position, and so forth. At their peak, around 1985-90, the AHA contests drew about 100,000 players in each contest, with a new contest starting every week. The Eternity puzzle (1999) and Eternity II puzzle (2007) were a tiling and edge-matching puzzles developed by Christopher Monckton, for which a £1 million and $ 2 million prize could be won.
Revised:  The puzzle was designed by William Sunners, a Brooklyn schoolteacher for a fee of $15,000 (roughly 4 years salary in that era). In the 1950s the focus of puzzle contests became fund-raising. Organizations such as the Boy Scouts and the Salvation Army would advertise their contests in large-circulation magazines. These contests either had an entry fee to play, or required a donation to the sponsoring organization. The most popular format for these contests was a picture composed of digits. The player had to correctly add all of the digits. The final tiebreaker would require the player to draw a path through a grid of several hundred numbers to obtain the highest possible total. Modern era The current era of puzzle contests, in which the contests are conducted almost entirely by mail, began in the early 1970s. A promoter of packaged vacation tours called American Holiday Association (AHA) decided to use a puzzle contest to publicize its holiday packages. The puzzle contest proved so popular, that eventually AHA dropped its vacation business and became exclusively a puzzle contest promoter. The best-known of the AHA contests was their BINGO format word grid. In the first round the player had to fill in 5 words into the 5x5 grid, meshing with the word BINGO that had already been filled into the left column. Since there were only 2 words in the word list starting with B, only 2 words with I, etc., no real skill was required. The second round was similar, with BINGO filled in the diagonal. Again, there were only 2 words starting with B, only 2 words with I in the second position, and so forth. At their peak, around 1985-90, the AHA contests drew about 100,000 players in each contest, with a new contest starting every week. The Diamond Dilemma was a 160-piece 3d triangular tiling puzzle with a £250,000 prize for a full solution. The prize went unclaimed by the 1990 deadline, though prizes for easier subproblems were awarded. The Eternity puzzle (1999) and Eternity II puzzle (2007) were a 209-piece tiling and a 256-piece edge-matching puzzle developed by Christopher Monckton, for which a £1 million and $ 2 million prize could be won.
Edit intent: fluency