Chicago is among the largest cities in the U.S. Famed for its bold architecture. You will not thinked about
that, but this city one of the cleanest cities in the world.There are more than 2 million square feet of
rooftop gardens and a well-developed network of public transport that help reduce pollution. The city is the birthplace of the skyscraper, and considered the most influential architectural city of the 20th century.