Last Wednesday, 72,312 people packed into Atlanta's Mercedes-Benz Stadium.

Not to watch the Falcons. To watch a soccer match.

An exhibition soccer match. 

Yep, 70,000-plus fans went to see the MLS All Stars play Juventus, last season's Serie A champions -- even though the Italian side didn't include global superstars like Cristiano Ronaldo and Gonzalo Higuain. 

A night like that may come as a surprise to you, especially if you've long grown tired of hearing that soccer is "the sport of the future." But it shouldn't. 

A recent Gallup poll shows soccer ranks second in popularity only to football among the coveted 18-34 demographic. Average 2017 MLS attendance was over 22,000, third behind the NFL and major league baseball. Atlanta United FC, owned by Home Depot co-founder and Falcons owner Arthur Blank, entered the league in 2017 and averages over 52,000 fans per game.

Yep, 52,000.

Portland will add more than 4,000 seats to Providence Park to meet demand. Los Angeles FC, a franchise that debuted this season, has sold out every home match so far in its brand-new, $350 million Banc of California Stadium located downtown.

And where there's success, smart money follows. The LAFC ownership group includes entrepreneurs like Larry Berg, Bennett Rosenthal, Peter Guber, and YouTube co-founder Chad Hurley, as well as Will Ferrell, Magic Johnson, and Tony Robbins. 

Ownership groups in Nashville and Cincinnati were recently awarded franchises, each paying a $150 million expansion fee for the privilege -- and promising to build $275 million and $215 million stadiums, respectively.

(For comparison purposes, Toronto paid $10 million for a franchise in 2007 that is now worth an estimated $280 million; Portland paid $35 million in 2011 for a franchise now worth an estimated $268 million; Montreal paid $40 million in 2013 for a franchise now worth an estimated $175 million. And Orlando City recently sold a minority ownership stake for an amount that resulted in a $500 million valuation for the franchise.)

But possibly the smartest money belongs to David Beckham. After working to bring a franchise to Miami for several years, Beckham finally succeeded with a new ownership group that includes billionaire SoftBank founder Masayoshi Son, Mastec owners Jorge and Jose Mas, and former Sprint CEO Marcelo Claure. 

As part of his 2007 contract to come to the MLS, Beckham negotiated an option to buy a franchise for $25 million when his playing career ended. At the time, $25 million for a franchise sounded like a lot, especially compared with the $10 million Toronto paid that same year. 

Today, $25 million is a steal. (Yet another reason it's good to be David Beckham.)

Other fun facts: MLS currently rakes in approximately $90 million per year from its broadcast partners. A new six-year apparel deal with Adidas is worth $117 million, almost five times the amount of its last Adidas contract. That deal runs through 2024, which is perfect timing for the league since the 2026 World Cup will be held in 16 cities across the U.S., Canada, and Mexico. The league's TV deals expire in 2025, just one year before the World Cup. 

How's that for perfect timing for new contract negotiations?

And Liga MX (the top league in Mexico) and MLS recently kicked off a long-term initiative that starts with an annual competition between the champions of each league, the Campeones Cupa, and will include other joint ventures, including a possible all-star game. The goal is to lift both leagues -- and North American soccer in general.

So why has MLS grown so popular among fans and become such a solid investment for entrepreneurs? 

Some reasons are obvious. The bulk of U.S. immigrants arrive from soccer-playing countries. Soccer also continues to grow in popularity at the grass-roots level (two of my kids played high school soccer), which creates a natural source of fans.

Team payrolls have also steadily increased, making room for household names like Rooney and Vela and Zlatan to add luster to the league, and for emerging talent as well.

For example, Atlanta's Josef Martinez and Miguel Almiron are among the best players in the league. (And easily two of the most exciting.)

The league asks teams to invest more than just franchise fees and player salaries. Current owners are expected to constantly invest in stadium improvements (hence D.C. United's new stadium, Audi Field), better training facilities, and player development.

The same holds true for new owners. Beckham's current plan includes building a 28,000-seat, privately funded stadium, public soccer fields, a technology park, and a conference center complete with hotels, retail stores, and restaurants. (City commissioners, though, have been reluctant to sign off on various plan iterations, which may be the only reason it's not always good to be David Beckham.)

Just as important, though, the league has focused on improving not just the product but also the fan experience.

Take Atlanta. Or Portland. Or Seattle. Or a number of other cities. Most fans stand the entire game. They chant, they sing, they cheer. They love the game but they also love the experience. They take pride in their teams. They take pride in their cities.

It's tribal. It's community. 

It's a melting pot.

Everyone belongs. 

Which is why, some years from now, soccer may turn out to be the most American of American sports. 

And while a rising tide never seems to float all boats equally, it's an incredibly good investment for savvy entrepreneurs.