Fort Christiansvaern is a historic fort located in Christiansted, U.S. Virgin Islands. Built in the 18th century by the Danish West India Company, it was designed to protect the island from pirates and foreign invasions. The fort features sturdy stone walls and a distinctive octagonal shape, reflecting the military architecture of its time. Today, Fort Christiansvaern is part of the Christiansted National Historic Site and serves as a popular tourist attraction. Visitors can explore its well-preserved structures, learn about the island's colonial history, and enjoy scenic views of the surrounding harbor.