FOXBOROUGH, Mass. -- Before Bill Belichick canceled the New England Patriots' final two voluntary organized team activities this week, he transformed parts of Gillette Stadium into a real-life "Back to the Future" movie.

Specifically, Belichick made Tuesday a wide-ranging history lesson on the roots of football, essentially creating an environment in which players were going back in time. That, of course, meant that there were leather helmets on the practice field, digital clocks covered up in the team meeting room, black-and-white recordings of old football plays shown, and a no-frills lunch menu that resembled what players in the 1930s and 1940s might have eaten (e.g., hamburgers and hot dogs rather than sushi).

"It was a lot of fun. We walked in and you could tell something different was going on than the normal practice day," explained one player.

The 66-year-old Belichick, who had surprised many on the team the day before by taking the team to Fenway Park, has a well-documented appreciation for the history of the game. Now in his 19th year as head coach, he has been likened by some players over the years to a professor because of his teaching-based approach.

"The thing I've learned about Coach Belichick is that he loves history, loves the military, and any time he can incorporate teaching us about that, he loves to do it," said one player who took part in Tuesday's turn-back-the-clock day.

"It was cool for him to get a chance to teach us about the sport that we're in, the National Football League and kind of how it started. We got to watch some old clips from football back then -- the '30s and '40s -- that I had never seen before. I didn't know what type of offenses were run, so it was really neat to see. We even looked at high school football back then, all the way up to NFL."

The discussion, with players in the room as young as 21 and coaches as old as 70, went beyond football.

"You think about it, if it was at a certain time back then, a lot of us wouldn't be playing. We would have been drafted and fighting for our country [in World War II]," said a player. "When we do stuff like that, it's special."

Earlier in the offseason program, Belichick surprised players by having Kobe Bryant speak to them, and Bryant watched the team practice that day. That was another highlight of what one member of the organization felt was a good offseason for the team, extending beyond the team's official offseason program.

Belichick told reporters multiple times throughout the spring that the overarching goal was to teach the team's system and give players the best chance to be ready for the start of training camp in late July. That includes team bonding, so while there was significant media spotlight on quarterback Tom Brady and tight end Rob Gronkowski not attending voluntary workouts, there were still positive steps taken in that area.

On Tuesday, owner Robert Kraft touched on the decision to cancel the final two OTAs, saying, "Part of that is that there were great things that happened last week, having everyone here, and then [Monday] they had a team-building activity that was really good."