These cool heatmaps show the most popular running routes around the globe

Running and cycling are great for your health.

They also have the potential to create some pretty cool images.

Strava, the popular fitness tracking app for runners and cyclists, tracked 140 million rides and runs from January 2014 to May 2015, and overlaid the results on Google Maps.

Bank of America Merrill Lynch used one of the images in a report out this week, which highlighted the growing popularity of athletic wear in the US.

That market has grown to $65 billion in 2015, according to the note.

Business Insider has pulled together a bunch more images from Strava. Scroll through some of the world's major cities, and how people run through them below.

Images come from Strava Lab's heatmap.