Once you start running, it is hard to stop. Most people who decide that they are going to conquer a marathon find that once they do one, they’re hooked. So it makes sense that, as you are training this season for that local marathon, you have bigger aspirations in mind. If you are looking to train for marathons of a lifetime, here are the top 10 marathons worldwide that should make your “must-run” list.

1. The Chicago Marathon is probably the most popular, non-qualifying marathon. Held every year since 1977 during the cool Midwestern fall, this mostly flat course is open to the first 45,000 runners who sign up, though only those who complete it in 6.5 hours or under are considered competitors. A great course for setting both personal and world records, the Chicago Marathon is considered one of the six World Marathon Majors as well as an IAAF Gold Label race.
2. The New York Marathon takes participants through all five boroughs of the city, allowing runners to truly appreciate every aspect of the Big Apple. This deceptively hilly race begins in Staten Island and winds its way through the city with the use of the many bridges and park trails. Held on the first Sunday in November, the New York Marathon draws one of the largest crowds in the world, with runners being chosen by a lottery system and is limited to 8.5 hours for completion.
3. The Boston Marathon makes the list for more reasons than just its recent infamy. Hosted every year on Patriot’s Day, it was first run in 1897, making it the world’s oldest annual marathon. The Marathon starts downhill through the iconic city streets, and then, turns upward at Heartbreak Hill and continues that way until the finish line is in sight. Boston Marathon competitors must qualify by completing a previous marathon within the last 18 months, and cross the finish line within specific time limits defined by age and gender.
4. Many runners are choosing to experience a world wonder in a new way by tackling the newly popular Great Wall Marathon. Participants are challenged to scale 5,164 stone steps and attempt to keep their footing while running along the steep ascents and descents of the Huangya Pass. Though runners have only been competing here since 1999, the race has already gained a great following, with over 2,500 runners participating in 2013.
5. The London Marathon has taken place every spring in the UK since the ’80s. The mostly flat course follows the River Thames, with three different starting points to accommodate the large crowds. Because of its simplicity, the London Marathon is one of the fastest and most competitive marathons. One of the World Marathon Majors, the London Marathon also presents its winner with a $1 million prize purse.
6. Another marathon conducive to fast times and high competition is the Berlin Marathon, which boasts the most world record holders. Taking place on the last weekend in September, it is known for its flat and even course, loud cheering spectators, and mild autumn temperatures. With the only limitation being that runners must be at least 18 years of age to compete, the Berlin marathon has grown to over 40,000 participants from over 107 countries.
7. It is not hard to understand the popularity of the the Big Sur International Marathon, which takes contestants along California’s Pacific coast. This scenic run down Highway 1 is limited to the first 4,500 qualified entrants who are at least 16 years of age or older, and who meet certain health requirements. Runners are given a six-hour time limit to battle the hills and wind, but, in true California style, are greeted at the finish line with celebratory cocktails.
8. Competitors who have already mastered the flat-track marathon will find an entirely new challenge at Colorado’s Pikes Peak Marathon. Its claim to be “America’s Ultimate Challenge” seems appropriate for a course where runners climb over 7,815 feet for the first half of the race, and then tackle a steep downward descent for the second half. Loose dirt, rocks, and other natural obstacles pepper the running trail as well. As if that is not enough of a challenge, high altitudes and varied weather conditions are also a major part of the race. In fact, the change from intense heat to biting cold and snow has made winning racing times vary more in this marathon than any other. A maximum of 800 participants a year are allowed.
9. The Honolulu Marathon is perhaps the most popular marathon among first-timers. With no limit on the number of applications or qualification requirements, the Honolulu Marathon has become one of the biggest marathons in the world, with over 30,898 entries in 2012. Popular among the military and the Japanese, it also boasts one of the best completion rates, with about 82 percent of entrants crossing the finish line.
10. Competing in the Athens Classic Marathon gives runners a total appreciation of the sport. The Athens Classic celebrates the myth of the very first marathon, in which Pheidippides ran from the Battle of Marathon to Athens to announce the Greek victory over the Persians. Continuously growing, over 7,000 competitors will strive to complete the challenging, mostly uphill course in early November. The race features the running of the Marathon flame from the Battle of Marathon Tomb to Marathon Stadium every year before the start of the race, making racing here a truly unique experience.

Image courtesy Wikicommons user Sillyfolkboy