Very few road races around the world carry as much significance as the Boston Marathon. Not everyone can meet the strict qualifying times, and those that do face a grueling 26.2-mile course through the Boston suburbs and (eventually) into the city itself. Whether you're running, spectating, or following from afar, read on for more about the prestigious competition, now in its 121st year.

1. THE MARATHON IS HOSTED BY THE BOSTON ATHLETIC ASSOCIATION.

Established in 1887, the Boston Athletic Association's stated mission was to "encourage all manly sports and promote physical culture." Ten years later, it hosted a 24.5-mile road race for 15 participants (only 10 of them made it to the finish line). The Athletic Association's symbol, the unicorn, still appears on today's Marathon medals.

2. THERE IS A LOGIC TO THOSE NON-TRADITIONAL MILE MARKERS.

Whereas most races post pretty straightforward mile markers—"Mile 1," say, or "Mile 15"—Boston, in its early years, included seemingly-random numbers. (Running legend Amby Burfoot recalled thinking that the 19 7/8 mile marker he spotted during his first Boston Marathon was especially ridiculous.) The signs weren't just for quirk's sake though—the checkpoints were chosen because they helped race officials easily locate the transportation they needed to get from checkpoint to checkpoint.

3. AROUND 500,000 SPECTATORS CHEER ON THE RUNNERS EACH YEAR.


Approximately half a million people show up to watch 30,000 runners every year, giving the local economy a massive boost. This year, the athletes, their families, and fans are expected to spend $192 million around town—or about $311 for every Boston resident.

4. ATHLETES DREAD THE COURSE'S INFAMOUS HEARTBREAK HILL.

Even non-runners feel their pulses start to quicken at the mention of Heartbreak Hill, located between miles 20 and 21. Boston Globe reporter Jerry Nason gets credit for coining the term after the 1936 event. During that race, as runner Johnny Kelley passed his rival Tarzan Brown, he gave him a pat on the back—a move that infuriated Brown and fueled him to a first-place finish. Nason wrote that Brown "broke Kelley's heart" at the hill.

The hill itself isn't as high as its fearsome name suggests: it climbs just 91 feet, according to Runner's World. (By contrast, the hill runners face near the start of the Marine Corps Marathon rises 211 feet.) But a number of other factors contribute to its reputation. For one, it's late in the race, and the rate of the change in elevation catches even elite runners by surprise.

5. CELEBS HAVE TO QUALIFY TOO (OR RUN FOR CHARITY).

Turlington Burns at the London Marathon in 2015

Unlike other races that admit celebrity runners, celebs who run Boston also have to meet the stringent qualifying standards. Or they have to be running for a charity, in which case they need to be able to finish in six hours or less. Some past celebrity participants include Will Ferrell (who ran in 2003 with a time of 3:56:12), Lisa Ling (she ran in 2001, finishing in 4:34:18), NKOTB alum Joey McIntyre (he ran it in 2013 and 2014, finishing in 3:57:06 and 3:48:11, respectively), and Christy Turlington Burns, who posted a time of 4:09:27 in 2016.

6. CHEATING HAPPENS MORE THAN YOU'D THINK.

At the 25-mile mark of any marathon, most runners are sweaty and a little dazed (at best). So when a fresh-faced Rosie Ruiz appeared out of nowhere a little over a mile from the finish line and went on to win the 1980 women's title, observers were immediately suspicious. After fellow runners complained that they hadn't seen her at all along the course, Ruiz was stripped of her medal. It was also revealed that she took the subway for a portion of the only other race she'd run, the New York City Marathon, and lied in order to gain admittance to that Boston qualifier, claiming she had a fatal brain tumor.

Ruiz wouldn't have stood a chance against Derek Murphy, a blogger and amateur investigator who has made it his mission to catch marathon cheaters. Since he started his blog in mid-2015, Murphy has caught around 250 cheaters, many of whom faked race times in order to qualify for Boston.

7. THE MARATHON WASN'T ALWAYS ON A MONDAY.

Up until 1969, the marathon took place every April 19, the same day Patriots' Day—a civic holiday commemorating the Battles of Lexington and Concord—was observed. That year, however, officials designated the third Monday of April as Patriots' Day, and the Boston Marathon organizers followed suit. Today, many refer to Patriots' Day as "Marathon Monday."

8. THE RED SOX DO THEIR PART TO SUPPORT THE RUNNERS.

For decades, the Red Sox have held a home game that kicks off at 11:05 a.m. on Patriots' Day. When the game ends, fans and players alike find themselves in Kenmore Square, cheering runners on in the last mile.

9. THE BOSTON MARATHON IS LARGELY RUN OUTSIDE OF BOSTON.

Before hitting Boston proper, runners take the scenic route through Hopkinton, Ashland, Framingham, Natick, Wellesley, Wellesley Hills, Newton, and Brookline. Participants don't cross into Boston until after 24 miles in.

10. BIB NUMBER 261 IS THE STUFF OF LEGEND.

In 1967, Kathrine Switzer became the first woman to officially run the Boston Marathon. (Bobbi Gibb had been the first woman to complete the race a year prior, but as an unregistered, or "bandit" runner.) At the time, Boston Athletic Association rules prohibited women from participating, so Switzer registered using her initials, "K.V. Switzer." The morning of April 19, 1967, runner no. 261 took her place among the other registered runners, initially blending in thanks to her gray sweatsuit. But a couple miles in, race organizer Jock Semple spotted her. Enraged, he tried to pull her off the course; her boyfriend at the time body-checked him, and Switzer kept running. The incident—and the shocking photos that resulted—launched Switzer, and women's running, to the forefront of a national conversation about women's place in the world of sports.

Switzer would go on to run several more marathons and would become a tireless advocate for female runners. This year—50 years after she was nearly shoved off the course of her first marathon—the now-70-year-old is returning to Boston to run it all over again. Once she crosses the finish line, the Boston Athletic Association plans to retire number 261, marking just the second time in its history it has retired a bib.

11. SINCE 2013, THE MARATHON HAS COME TO EMBODY HOPE AND RESILIENCE.


The two bombs that detonated near the finish line in 2013 killed three people and injured more than 260 athletes and spectators. But instead of backing down, the city of Boston rallied around the more than 36,000 runners who showed up to take on the legendary course the following year. Approximately 1 million spectators cheered on the participants, including Meb Keflezighi, who became the first American to win the race in 30 years and, at 38, the oldest winner since 1930. To honor the victims of the bombing, Keflezighi wrote their names in Sharpie on his bib before pinning it on his singlet. "I just said this is Boston Strong," Keflezighi recalled earlier this month. "I want to write their names big so I can get their strength. To have that inner motivation was huge."

All images via Getty unless otherwise noted.

A version of this story originally ran in 2011.