CANTON, Ohio -- Located just off Interstate 77 in northeast Ohio, the Pro Football Hall of Fame houses the history of the NFL and its greatest stars.
For 47 years, it's been holy ground for the football fan. It's a place where fans can lose themselves in more than 83,000 square feet of photos, highlights and artifacts of their favorite teams and players. It's a place where moments from the earliest days of the league to the modern era remain alive.
But beyond what fans see on television and read in magazines or online, what is it that we don't know about the Hall of Fame? For every display of Hall of Famers Jim Brown, Dan Marino and Otto Graham, there are lesser-known players who have shaped pro football just as much as the stars.
Leland Melvin seemingly doesn't belong in any Hall of Fame discussion. He doesn't hold any NFL records. He never made a game-winning catch in the Super Bowl. His career highlights will never be seen on NFL Films.
Still, this museum features a display honoring a player who never once played a down in a regular-season game.
What makes him special? Melvin is the first former NFL player to become an astronaut and fly on a mission in space.
Melvin was an 11th-round pick of the Detroit Lions in the 1986 draft. The wide receiver from the University of Richmond was an honorable mention All-American in his junior and senior seasons and graduated as the Spiders' all-time leader in receptions (198) and yards (2,669).
He never made it out of training camp. Nagging hamstring injuries curtailed his time with the Lions and later the Dallas Cowboys and the Canadian Football League's Toronto Argonauts.
Even though his football career ended, Melvin had a great fallback: his brain. An NCAA Division I Academic All-American at Richmond as a chemistry major, he later earned a master's degree in materials science engineering from the University of Virginia. He eventually joined NASA.
For nearly 11 days in November 2009, Melvin was a part of NASA's space mission crew from Flight STS-129. It was the 31st flight to the International Space Station and the second shuttle mission for Melvin. He took Lions and Cowboys jerseys, a football with every Hall of Famer's name inscribed on it and a coin that eventually would be used in Super Bowl XLIV.
"The jerseys were stored in the mid deck," Melvin said in a phone interview. "Once we reached space, it felt like I had four or five linebackers on my chest."
While his NFL career never quite took off the way he wanted it to, Melvin, now 46, has used his platform as an athlete and astronaut to help kids. He's participating in the Pro Football Hall Of Fame Festival this weekend to celebrate the Class of 2010's induction. Melvin has helped launch NASA's Summer of Innovation program, designed to help students achieve success in science, math and technology.
What comparisons can he make between football and space exploration?
"Going from college to the pros, it's another level," Melvin said. "It's just like going from a research scientist to becoming an astronaut. There's teamwork involved. There are very strong parallels."
It's the lesser-known gems like Leland Melvin who make Canton pro football's ultimate destination, from the smallest detail to the most well-known highlight.
We know about the busts. We know about the footballs that are kept there to mark notable games, broken records and milestone achievements. We know about the enshrinement ceremony that takes place every summer in Fawcett Stadium adjacent to the Hall.
What else is there? We decided to find out for ourselves. Call it a scavenger hunt or deep investigative reporting; ESPN.com was given full access for a day in Canton. It was an opportunity to sift through all the nooks of the Hall and see what we could find hidden inside pro football's attic.
Contracts of Marion Motley and Bill Willis
A year before Jackie Robinson made headlines by breaking Major League Baseball's color barrier, Marion Motley and William (Bill) Willis made a quieter -- but no less important -- entrance into professional sports when they signed with the Cleveland Browns of the All-America Football Conference in 1946.
These two contracts represent a historic moment in pro football history. From 1919 to 1933, a smattering of black players played for several integrated pro teams. But during the era bridging the Great Depression and World War II, there were no black players in the NFL. When the rival AAFC emerged in the late 1940s, NFL teams started to integrate again.
Both players would enjoy Hall of Fame careers: Motley was inducted in 1968 and Willis in 1977.
Immaculate Reception turf
There's the Immaculate Reception and then there's the Divine Intervention.
Harris wanted to maintain a piece of that history, so after studying photos, the running back was able to pinpoint the exact spot where he made the catch in Three Rivers Stadium.
However, what he didn't know was that stadium employees would be removing the turf at season's end. The Hall of Famer arrived just as the field crew was replacing the turf and was able to cut out the spot and grab his piece of history.
Football's 'birth certificate'
Described as the most precious document in the Hall of Fame, pro football's birth certificate is the first indication of someone receiving payment for his on-field performance.
In 1892, the Allegheny Athletic Association fielded the first professional team. William Heffelfinger, the first professional football player, was paid $500 to play in a game against the Pittsburgh Athletic Club.
The contract shown here is the first visual proof of a pay-for-performance agreement.
While replicas are on display at the Hall, the original contract is located in a special archives section in Canton. To preserve the document, the page was sent to a conservator and was reinforced with Japanese paper.
Leland Melvin display
Leland Melvin was drafted by the Detroit Lions in the 11th round of the 1986 draft. He was the University of Richmond's all-time leader in receptions (198) and yards (2,669) and an honorable mention All-American in 1984 and 1985. During Lions training camp, he was sidelined by hamstring issues and later released. Melvin had a brief tryout with the Dallas Cowboys before the lingering injury forced an end to his football career.
Melvin would later begin a career in the space program, and in 1998, he became an astronaut. A veteran of two space flights, STS-122 in 2008, and STS-129 in 2009, Melvin has logged more than 565 hours in space.
Red Grange's broadcast 'guide'
Following his Hall of Fame playing career with the Chicago Bears and the now-defunct New York Yankees, Harold "Red" Grange had a successful career as a color commentator for Bears games and NBC's college football game of the week in the 1950s.
Before the computer age, when monitors assisted broadcast teams in keeping track of which players were on the field, Grange used a specially made board to keep up with the action so he could accurately relay it to his viewers. Each player's number was written on a cork and placed in the positional holes carved in the board for offense and defense.
As players would be rotated in and out of the game, Grange would be able to keep track of who was on the field by simply replacing the corks.
Red Grange's ice block tongs
Without a doubt, one of the unique items we found was a set of ice block tongs "The Galloping Ghost" used while working a part-time job as a student at the University of Illinois.
Grange, also known as the "Wheaton Ice Man," would not only use this job as a moneymaker, but the ice toting helped him build core strength when he wasn't playing football.
His name is engraved on the tongs.
Giants' defensive game plan from Super Bowl XXV
Long before he led the New England Patriots to three Super Bowl titles in four years, Bill Belichick built his reputation as a mastermind defensive coordinator for the Giants in the 1980s. Under the tutelage of Bill Parcells, Belichick helped build one of the dominant defenses in the NFL. In the 1990 season, the Giants led the league in fewest points allowed (211). However, in Super Bowl XXV, the Giants faced a Buffalo Bills team that had the NFL's best offense, scoring a league-leading 428 points in the regular season.
The Giants' defense, led by Pro Bowlers Erik Howard, Pepper Johnson and Lawrence Taylor, eliminated the big plays and beat Buffalo 20-19. New York dominated the time of possession with a Super Bowl-record 40 minutes, 33 seconds.
Scrapbook of archives
Believe it or not, there was a time when the media wasn't a 24/7 blitz that gave voice to everyone with an opinion. In the early years of the league, game coverage consisted of just newspapers, radio and some television. Fans who missed the game usually had to wait until the next morning's paper to learn how their team fared.
Located in the archives of the Hall of Fame is a scrapbook of news clippings from media across the country. From columns to cartoon illustrations, the scrapbooks give a detailed look at how the league was covered in the early to mid-20th century, and show a contrast in the traditional journalism of old versus the new media of today.
Beadle's Book of Football
One of the most popular literary "franchises" during this time was the Beadle's Dime Novel series. One of the first known books on football was the Dime Book of Cricket, published in 1866. While the first two-thirds of the novel are on cricket, the final third focuses on football. The section is mainly on the rules of the game and focused primarily on soccer and rugby, which at the time were more popular than pro football.
The Hall of Fame has one of only six known copies of the publication.
Jamar Hudson is an editor at ESPN.com. Thanks to Joe Horrigan, VP Communications/Exhibits, Pro Football Hall Of Fame, and the Hall's staff for granting ESPN.com access.