30 días en bici is the Spanish campaign of 30 days of biking an international, one-month event for promoting the bicycle use. It consists in riding every day in the April month and taking photographs. Participants share images online. The American version, the pioneers, use the hashtag #30daysofbiking.

Founded in 2010, 30 days of biking started in Minneapolis, Minnesota. Its power lies in its simplicity. Bikers just need to pledge to bike everyday in April, no matter the weather (indoor photos are welcomed), and share their adventures. An easy and powerful idea as thousands follow it around the world.

Why 30 days? Rumor has it, one of its founders read a paper about developing a yoga habit by practicing it for 30 days. Then he asked himself if 30 days were enough to develop a habit, why do not we use it to promote the bike use? Again, easy and powerful.

Ok, but why April? April was chosen as the ideal month since is the first complete month in Spring and people love it after the Winter. Moreover, daylight hours increase (in the north hemisphere) and hence riding is increased at least for those who appreciate moderate temperatures.

The Spanish version has spread to more than 50 cities. It started in 2013 thanks to a bikeaholic group leaded by Carlos Rodriguez. But they do not limit the activities they do to April. Their ambitious targets tend to generate a social change by promoting the bicycle daily use, inspiring bikes as the main way of transport, educating citizens about the benefits of using the bike regarding health, and transforming cities in human-friendly spaces and caring for the planet.