Today if you visit Amsterdam, you'll see bikes everywhere - they rule the road! But that wasn't always the case. Fifty years ago, Amsterdam was so crowded with vehicles that bicyclists could hardly move. But mums and kids relied on their bikes to get from place to place in the city. What could they do? Women like Maarjte van Putten and her friends led protests, and one day, a whole swarm of women and children took over the new big tunnel meant just for vehicles to show what a little pedal power could do. They were arrested, but when the women and children arrived to cookies and lemonade at the police station, they knew they were well on their way to making a big change.