New York's former mayor and Vancouver's mayor Gregor Robertson are pushing for climate change policies at the city level.
British author Mark Ovenden has had a fascination with railways since he was a child.
Growing up in the 60s, he and his dad used to explore abandoned railway stations and old trains. He also collected maps of the various railways.
Last year he published a collection of some of his favorites in the book “Great Railway Maps of the World.” As he tells Monica Brady-Myerov, railway maps are a window into the development of a country.