Major League Baseball returns to the U.K. as the New York Mets and Philadelphia Phillies square off in the 2024 London Series beginning Saturday.

The two National League East division rivals will meet for a pair of regular-season games from June 8-9 at London Stadium.

While the on-field action is sure to be exciting, here’s a guide to what else to watch at the ballpark when MLB comes to London for the third straight season.

Batting practice

A few hours before each game starts, both teams will get plenty of time on the field to fine-tune their swings. Hitters will rotate in and out of the batting cage, performing drills like bunting or simply swinging away. Fans are encouraged to arrive early to take home souvenirs, but if you’re not baseball-hunting, still keep an eye out for errant projectiles all over the stadium!

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Starting lineups

Each team will finalize its starting lineup before the beginning of the game, and those lineups will be announced over the public-address system inside the stadium and shown on the scoreboard. Each team will list 10 starters -- a nine-man starting lineup (including a designated hitter) as well as a starting pitcher.

Ceremonial first pitch

Typically a few minutes before the teams take the field, a special guest will be invited to throw out the ceremonial first pitch. (Many games feature several such first pitches.) Standing in front of the pitcher’s mound -- or on it, if they’re feeling confident -- they’ll make a toss to a player or coach from one of the teams, who stands near the plate. Some less-than-professional pitchers manage to throw perfect strikes … some, not so much.

National anthems

“The Star-Spangled Banner,” the national anthem of the United States, will be performed before each game. Players, coaches and umpires will line up along the baselines and stand in silence during the anthem. Everyone will be asked to remove their cap or other headgear before the song begins. The national anthem of the U.K., “God Save the King,” will also be played at London Stadium for the 2024 London Series.

Replay review

When they disagree with certain rulings, including fair-or-foul calls or tag plays, teams have the chance to overturn calls thanks to MLB’s replay review system. A video review at MLB’s Replay Command Center in New York can be initiated by a manager challenge or by the chief of the umpiring crew. Each manager receives one challenge per game and can receive another if the first is successful. During the 2023 London Series, for example, the Chicago Cubs challenged and successfully overturned a forceout call at second base.

Between-innings warmups

After the third out of each half-inning is recorded, there will be a two-minute break while the teams change sides. The fielding team will get an opportunity to warm up, with infielders practicing ground balls and outfielders typically playing catch. The pitcher will deliver a series of warm-up pitches, while hitters from the opposing team stand off to the side, typically watching the pitcher’s delivery and timing their swings.

Mascot races

Depending on the team you’re watching, you might see something unexpected: a mascot race! Several MLB teams host mascot races, featuring competing characters sprinting around the warning track in the outfield, during inning breaks. The Milwaukee Brewers’ Famous Racing Sausages, the Washington Nationals’ Racing Presidents and the Pittsburgh Pirates’ Great Pittsburgh Pierogy Race are some of the most famous mascot races in MLB.

Mound visits

Each game, MLB coaching staffs can make four visits to the pitchers’ mound without having to remove their pitcher. Mound visits are limited to one per inning (on the second trip to the mound in the same inning, the pitcher must be removed) and to 30 seconds in duration. Managers or pitching coaches will call timeout before approaching the mound to meet with the pitcher. For every extra inning, each team receives one additional mound visit.

Pitching changes

Pitchers are often replaced between innings, but pitching changes can also be made in the middle of a half-inning. A pitcher must face at least three batters or complete a half-inning before he can be removed. For mid-inning pitching changes, there will be a two-minute break while the new pitcher enters from the bullpen and warms up on the mound.

Seventh-inning stretch

In the middle of the seventh inning, after the visiting team has batted, fans are given an opportunity to take a bit of a break from the intense action. During the seventh-inning stretch, the song “Take Me Out to the Ball Game” is played in the stadium while fans stand, cheer and sing along.

Extra innings

Is the score tied after the bottom of the ninth? That means the game is heading to extra innings, which will be played until a winner is determined. Each team will begin each extra frame -- starting with the 10th inning -- with an automatic runner on second base. The game is played as normal from there, and it ends when one team leads at the end of a complete inning. (Curious about the record for the longest game? It was a 26-inning marathon back in 1920.)