Climate Pledge Arena is a multi-purpose indoor arena in Seattle, Washington, United States. It is located north of downtown Seattle on the campus of the Seattle Center, a 74-acre (30 ha) civic and entertainment center first built for the 1962 World's Fair, the Century 21 Exposition. It sits on the site of the original Washington State Pavilion exhibition facility, subsequently bought by the city of Seattle and renovated in 1964 into a sports and entertainment venue, the Seattle Center Coliseum. Following an extensive $1.15 billion site redevelopment from 2018 to 2021, the new arena replaced the older facility, then named KeyArena. It reuses the original building's iconic roof and exterior window curtain walls, which were landmarked by the city in 2017 and added to both the Washington State Heritage Register and the National Register of Historic Places in 2018. An extended atrium on its south end houses the entrance to the modern venue. It holds a seating capacity of 17,151 for ice hockey, 18,300 for basketball, and up to 17,340 for concerts and other events.