If there's anything more American than apple pie, it surely must be baseball. Since the game's first ball was tossed out in Hoboken, N.J., in a contest between the local Knickerbockers and the New York Baseball Club back in 1846, the sport has flourished to become the "Great American Pastime."

An astonishing 74 million fans are expected to pass through the turnstiles of Major League Baseball's 30 parks this season, which begins April 5. Hand in hand with baseball's meteoric rise in popularity has been the corresponding development and expansion of stadiums across the country. Ballparks hosting MLB teams are, for the most part, grand in scale and serve as a source of great civic pride and income.

While playing fields must conform to certain league specifications, the facilities surrounding them vary considerably, representing the unique style and personality of the cities they represent — and no more so than in Boston, New York and Chicago. These parks are not just for games. All offer visitor programs that can make for an extraordinary experience during your stay in the city.

To learn what a visit might hold in store for you, we've selected the tour programs of seven major league ballparks for review, including, of course, the Big Three. So tip back that visor and read on!

1. Fenway Park — Boston

Let's begin with Boston's Fenway Park, the granddaddy of them all and home to the Boston Red Sox. Built in 1912, it is the oldest MLB stadium still in play. In fact, it is the oldest venue of any pro sports team in America. Fenway is an icon of American sports, often compared to Chicago's Wrigley Field as one of two "classic" major league ballparks still in use.

Fenway has undergone a number of renovations but remains pretty much true to the original. Visitors clamber to see the "Green Monster," Fenway's 37-foot, 2-inch-high left field wall, the highest in the majors. Fun fact: It has always been the same height but wasn't painted green until 1947.

Babe Ruth starred here as a Red Sox pitcher before moving on in 1919 to fame and fortune as a slugger for the rival New York Yankees— and that adds to Fenway's mystique. Ruth's uniform number and those of other former Boston greats, including Ted Williams and Carl Yastrzemski, are emblazoned on Fenway's right-field facade.

Fenway Park tours provide 60-minute guided walk-arounds of the ballpark, complete with team, ballpark and player history. Tours run daily year-round every hour from 10 a.m. to 4 p.m. and are handicap-accessible.

Adult tickets are $18, children (3-15), students and military are $12, and seniors are $17. Tour tickets are sold at the Gate D Ticket Booth on a first-come basis. For more information, call 617-226-6666 or visit the Red Sox's website here.

2. Yankee Stadium — New York

Unless you live in the Big Apple or follow baseball closely, you may not realize that world-renowned Yankee Stadium — a hallowed shrine of American sports dating to 1923 — was replaced by a new stadium in 2009.

In spite of objections from traditionalists, team owners decided on a new park, both to offer more comfortable seating and to add a long list of amenities.

A major makeover in the mid-'70s had already drastically changed the appearance of "The House That Ruth Built," forfeiting much of its original character. Most observers contend the new $1.5 billion stadium, erected across the street and incorporating many design elements of the 1923 original, better pays homage to Yankee history than the highly modified structure it replaced.

Yankee players took to the new park in a big way, capturing the 2009 World Series in the stadium's inaugural season. Fans and visitors approve as well, finding the new Yankee Stadium more comfortable and accommodating than its predecessor. The old stadium has been demolished, and a public park has taken its place.

Always a class act, the Yankees offer an excellent tour program. Available year-round (except on game days), hour-long Classic Individual Tours include visits to the clubhouse, batting cage area, dugout and Monument Park. The latter is an open-air museum located just beyond the centerfield fences where plaques and an array of large, red granite memorials honor Yankee heroes from the past.

Tours commence every 20 minutes, usually from noon to 1:40 p.m., and are handicap-accessible. Private and group tours also are available. Purchased online, adult tickets are $20; $15 for children up to 14, and seniors 60 and older. Add lunch to your tour at Hard Rock Cafe for $40 per person. For more information, call 646-977-8687 or visit the Yankees' website here.

3. Wrigley Field — Chicago

Nicknamed the "Friendly Confines," Wrigley Field is MLB's second-oldest ballpark behind Boston's Fenway Park. It was built in 1914 by Charles Weeghman for his Chicago Whales baseball team of the old Federal League. When the league folded the following year, he purchased the Chicago Cubs, who had been playing on the city's west side since 1893.

The Cubs played their first National League season at Weeghman Park in 1916. In the 1920s, the Wrigley family (of chewing gum fame) purchased the team and renamed the park Wrigley Field. The Wrigleys expanded the park during the 1930s, adding the famous 27-by-75-foot hand-operated scoreboard behind the bleachers in center field.

The old scoreboard remains in use today, serving as one of Wrigley Field's most historic elements. Ivy, planted in the 1930s, still clings to the outfield wall. Remarkably little, in fact, has changed at Wrigley Field since those early days.

You'll sense and feel the genuine nostalgia of the Friendly Confines during one of the park's daily tours. Guided walking tours for 2015 get underway in April and go rain or shine, visiting the press box, clubhouses, dugouts and the playing field. On nongame days, tours depart every hour from 9 a.m. to 5 p.m. Tours also are offered on game days, prior to game time, but check in advance for exact times.

Tours are wheelchair and stroller accessible and cover about 1.5 miles. Tours cost $25 per person, kids 2 or younger are free. Discounts are available for groups of 20 or more. For more information, call 773-404-2827 or visit the Cubs' website here.

All MLB cubs/stadiums welcome the public to enjoy similar visitor programs. Google your favorite team or go to www.mlb.com for links to all 30 teams and their ballparks. Most of these ballparks deserve mention for their visitor appeal and excellent tours, but here are four more we think rank among the best.

4. Oriole Park at Camden Yards — Baltimore

Baltimore's Oriole Park at Camden Yards is often described as baseball's most beautiful park. It arose from a sooty downtown railroad yard in 1992 to help lead a major inner-city revival and, some say, to revolutionize baseball.

Tours go for 90 minutes, four times daily, and include the Orioles dugout, press and suite levels, and the scoreboard control room. Tickets are a real bargain at $9 for adults, $6 for kids and seniors. For more information, call 410-547-6234 or visit the Orioles' website here.

5. Target Field — Minneapolis

If you're headed to Minneapolis, don't miss out on a visit to Target Field, home of the Minnesota Twins. Baseball's newest park when it debuted in 2010 (Marlins Field in Miami opened in 2012, making it the current newbie), this lavish $522 million layout in the city's downtown Warehouse District is worth seeing even if you don't care a thing about baseball.

Tours are 90 minutes and are rated by ESPN as the best in the majors. They are available on both nongame and game days from April to October, usually departing at 11 a.m. and 1:30 p.m. — but the schedule is complex, so contact the tour office for precise times. Tour prices are reasonable, ranging from $8 to $17. For more information, call 612-659-3877 or visit the Twins' website here.

6. Coors Field — Denver

Out west in Denver, Coors Field, which plays host to the Colorado Rockies, is another well-executed downtown park that figured importantly in the resurrection of its once-slummy surroundings — Lower Downtown, or "Lodo" to locals. Since play began in 1995 at this beautiful brick park with its stunning view of the Rockies, it has been among league leaders in attendance and batting offense.

A 70-80-minute tour is offered three times daily on nongame days and twice daily on evening-game days throughout the baseball season. Tours here are cheap ($10 adults, $7 for kids up to 12, $8 for seniors) and will inform you as to why a baseball travels almost 10 percent farther in the Mile High City. For more information, call 303-762-5437 or visit the Rockies' website here.

7. AT&T Park — San Francisco

AT&T Park, home to reigning World Series Champion San Francisco Giants, is a ballpark that should be on every baseball fan's bucket list. Replacing Candlestick Park in 2000, AT&T Park, nestled on the edge of San Francisco Bay near downtown, possesses charm, character and breathtaking views rivaled by few other parks in the country.

AT&T Park's 90-minute tours go behind the scenes to places only players, staff and media normally go — dugouts, the batting cage, visitor's clubhouse, the press box and a luxury suite. Except for certain unavailable dates, tours go every day at 10:30 a.m. and 1:30 p.m., with additional tours offered during June, July and August. Tour prices range from $12 to $17. For more information, call 415-972-2400 or visit the Giants' website here.