The South Sandwich Islands are located about 800 km (460 miles) south-east of South Georgia. The islands form a chain some 390 km (240 miles) long, comprising 11 major and several smaller islands. The islands are volcanic in origin and some remain active. There is at least one extraordinary wildlife spectacle within the South Sandwich Islands: Zavodoski Island is home to approximately 1,000,000 pairs of breeding chinstrap penguins on its volcanic slopes, making it one of the largest penguin colonies in the world. Those who have seen this massive penguin colony speak of it with awe.