Queen Anne Counterbalance

Lonely Planet review

The streetcar that chugged up and down the steep grade along Queen Anne Ave started operating on overhead-wire electricity in 1900, but it still needed some help to manage the hill. So engineers designed a system of counterweights – a 16-ton train that ran in a tunnel beneath the street would go up when the cable car went down and vice versa.

The cable cars were retired in 1943, but the underground tunnels are still there.