Commercial fishing on Lake Superior became important during the late 1880s, spurred by the arrival of Swedish and Norwegian immigrants to the North Shore. In 1890, the Merritt brothers discovered the Mesabi Range. The Two Harbors Lighthouse was built on Agate Bay in 1892. Ten years later, five Two Harbors businessmen signed the articles of incorporation for a new mining company named 3M. Today, 3M Corporation has over 70,000 employees worldwide and produces more than 50,000 adhesive household products, now has its headquarters in Saint Paul.