Since the first bike path was built in Brooklyn in 1894, over 200,000 New Yorkers cycle the streets every day. But this green and healthy shift has run into difficulties, so cyclists are crowdsourcing a map of cycling issues and hazard warnings to promote bike safety.

Whether its a hipster on their fixie, a banker on their Brompton or MAMIL (middle-aged man in lycra) on their road bike, city streets and country lanes in the UK are packed with cyclists. Around two million Brits now cycle at least once a week. What is making travelling by two wheels so popular?

Transport for London conducted the biggest mass census of cyclists to date, finding that bikes make up 24% of all vehicles on the streets during the city's morning rush hour. The finding gives traction to cycling advocates who demand better infrastructure.

Many claim that cycling makes people happier and healthier and cities greener, and a study in New Zealand shows that for every dollar spent on building separated bike lanes, cities could save as much as $24 thanks to lower healthcare costs, less pollution and traffic.