AT&T Park opened in 2000, and since then the venue has played host to the 2007 MLB All-Star Game, the semifinals and finals of the 2013 World Baseball Classic, and now four different World Series. During regular season San Francisco Giants games alone, over 48 million fans have gone through the turnstiles, gazed out at the spacious field, and taken in the breathtaking views of San Francisco Bay as they mentally catalogued every square inch of this modern-day jewel of a stadium. Over the last 15 years, the eyes of the baseball world have turned upon AT&T Park time and again, and its distinct appearance makes it instantly recognizable to fans around the globe.

And yet, even this well-known park has its secrets. Tucked inside the right field out-of-town scoreboard, in front of the world’s prying eyes, lies a secret that is like something out of a movie.

Only a select few—walking through a mysterious set of four glass doors facing out over McCovey Cove—are allowed to enter The Gotham Club. Perhaps the most unique in-stadium experience in all of professional sports, the club opened its doors this past July to current and former Giants players, as well as season ticket holders willing to pay the yearly membership fee. The cost of belonging is steep—$2,500 for initiation and $1,250 per year, plus whatever your ticket costs—and the membership numbers are incredibly limited (no more than 1,000 at a time), but the rewards of belonging are equally vast.

Giants CEO Larry Baer said at the grand opening that the Gotham Club “grew out of our commitment to celebrate the 132-year history going back to the New York Gothams and the New York Giants, before the franchise moved west,” and this idea certainly shows in everything they do. Built as a tribute to the club’s rich history, the main “Clubhouse” area looks like a 1920s-era speakeasy. Its leather upholstery, soft lighting, and ample collection of memorabilia make this place a haven for those who long for the old days of baseball and want to relive the franchise’s history dating back to its days on the other coast.

For the Giants organization, however, it’s not just about the novelty of having another cool feature to their already-admired park. Gotham Club manager Ryann Greenberg says that they are seeking to “to create a deeper connection between our fans and our history.” The Giants’ fans are a loyal and devoted bunch, although you wouldn’t necessarily know it given the relatively heavy East Coast bias of Major League Baseball coverage and the presence of the Los Angeles Dodgers just a few hundred miles down the road. But don’t let the dearth of media attention fool you; these fans care deeply about baseball, and their team, in turn, cares about them.

“We’ve had season ticket holders since Candlestick [Park, which opened in 1960 and was the home of the Giants until they moved to AT&T in 2000] that have been with the team in San Francisco since the beginning,” Greenberg says. “They’re very dedicated fans, so we just wanted to provide them with a very club-level experience in the ballpark while reconnecting them with the history of our team.”

In order to do so, the management team sought out underutilized spaces throughout the park and looked to convert them into usable spaces. Nothing was off limits—utility closets, a lounge, and even part of a conference room were commandeered to create what are now the three designated spaces for The Gotham Club: the Clubhouse, the Bullpen, and the Game Room. Each has its own unique features and charm, but each maintains a common link: an unflinching commitment to honoring the history of a club that began as the New York Gothams in 1883.

It hasn’t been to draw direct links to the past, though. Finding all of the amazing memorabilia that they have on display has been incredibly labor intensive and has indeed become a fan-wide mission. Greenberg routinely scours local flea markets for hidden gems, while Sales & Marketing Director (and San Francisco native) Joey Nevin has plundered the garage of nearly every family member he has in search of the next great item to show to fans. Members, too, have gotten in on the action. Greenberg says that not only do they contribute pieces of memorabilia from their own personal collections, but several have offered to serve as de facto curators, donating their time in an effort to bring the best possible pieces to the club. But don’t let The Gotham Club’s emphasis on history fool you. It’s got all the modern amenities you could ask for, and more.

The Clubhouse serves as the main area for people to meet, and its full bar and dining room make it a go-to destination before, during, and after games. It offers seating with a view of the field, ice cubes shaped as baseballs, and even the chance to help swap out the numbers on the old-style scoreboard. In any one game, 300-500 people will stream through the Clubhouse starting three hours prior and ending 90 minutes after its conclusion. The unique perspective that the Clubhouse offers makes it a unique, singular experience in all of Major League Baseball. And it’s tough to beat the view.

“There are people who sit behind home plate and say that the Clubhouse seats rival those,” Greenberg says. “It’s a completely different vantage point that fans have never had before.”

If you’re just looking for some pregame entertainment, however, The Gotham Club has you covered there as well. Their Bullpen area is located on the ground level, and is adjacent to the warning track in right field. While it’s only open before the game, it offers fans a chance to stand literally right next to the players as they warm up and take batting practice. Best of all, fans also get to enjoy a cocktail while doing so—not a bad deal.

The third Gotham Club section—the Game Room—is perhaps the most absurd. Tucked away on the suite level and with no direct view of the field, it has the usual man cave staples (arcade games, pool table, TVs), but also has something that no other American sports stadium can boast: a fully operational bowling alley. Yes, if the baseball is not exciting enough for you, you can pop up to the Game Room and try your hand at an entirely different sport. Because hey, why not?

While it’s great to have options like this one, the club is really meant to enhance the stadium experience, not replace it entirely.

“Most of our members are season ticket holders, and they come to most of, if not all, of the games, so it’s fun for them to have a different experience each time they come,” Greenberg says. “We’ve seen people come before the game because they won’t leave their seats during it, and we have people who only come during the game because they can’t make it before the first pitch. The ways in which our members are using the space are different across the board.”

The Gotham Club has been a big success despite its brief existence, with membership already numbering around 700 individuals. It begs the question, then, where do they go from here? The idea for them is not to remain static but rather to look for new pockets in the park where unused spaces could be converted into new areas for members to enjoy. The Boston Red Sox ownership group has done this with ancient Fenway Park, building new food concourses, a roof deck in right field, and, of course, the famous Green Monster seats. But AT&T Park offers a singular experience that fans will not find anywhere else.

It would not come as much of a shock, then, if other teams tried to replicate the look and feel of The Gotham Club in their own stadiums.

“We hope that other people follow,” Greenberg says. “It would be great to have clubs and other ballparks that offer reciprocity to our members and say, ‘If you go to Fenway Park or Yankee Stadium, you can hang out in their club just like their members can hang out in our club.’”

It’s that sense of belonging and connecting directly with your favorite franchise that has made The Gotham Club such a draw. Because all current and former Giants players and coaches automatically belong, they have been known to pop in to mingle with the members, hammering home the idea that this club is something more than just a group of people willing to fork over a bunch of cash. It’s a community that’s driven by the same passion, and both the members and Giants organization want to celebrate that love for the team. The membership is made up of people from every demographic: young, old, male, female, retired, tech entrepreneurs, business professionals, and much more. It doesn’t matter as much who they are, but rather what they care about.

Ultimately, that is the ethos that sustains The Gotham Club. As Greenberg says, “the great thing about it is their shared love of the Giants. That’s what brings everybody together: they’re united by their Giants fandom.”