Barcelona just pulled off the wildest eco-hack: for five years, one of their main bus lines ran on fuel made from human sewage. Yep, they literally turned poop into power, cutting emissions by 80% compared to regular gas. Riders didn’t even notice the difference—no weird smells, just a greener commute. Now the city’s scaling up, showing the world that our waste could be the secret to cleaner cities. Who knew your morning flush could help save the planet? #Transportation #Barcelona #Sustainability