records often fall. John MacDougall/AFP/Getty Images

Whether you're one of the world's best or a back-of-the-packer, the BMW Berlin Marathon offers a chance for a world record or personal best. It's a flat course with long straightaways, just barely above sea level with generally mild weather. Bands along the course liven the atmosphere. The past six men's world records have been set at Berlin, the most recent by Kenya's Dennis Kimetto (2:02:57) in 2014.

History: Just 286 runners entered the first race in 1974, which covered only West Berlin. The course expanded to the former East Berlin upon unification in 1990. In 2016, more than 41,000 completed the race.

Key feature: On chilly days, runners can get hot tea instead of water at some aid stations.

Scenic highlight: Participants run through the2014. "I like Boston because of the tradition. If you are a marathon runner, you are measured based on the Boston Marathon."

History: The first race was 24.5 miles. In 1924, the course conformed to the Olympic distance of 26 miles, 385 yards.

Key feature: Heartbreak Hill gets all the attention, but it's just the last of the four rises of the Newton Hills between the 16th and 21st miles that can test tiring runners.

Scenic highlight: Runners can draw inspiration from the statue of race legend Johnny Kelley at the base of Heartbreak Hill. An old Kelley and a young Kelley are depicted running side by side holding hands. Kelley ran Boston 61 times and won it twice, retiring after the race in 1992.

Quotable: "I ran Boston for the first