Cape Lookout's lighthouse was completed in 1859 with the best technology available. Its double-walled brick construction was designed to support the 163-foot structure, and its state-of-the-art Fresnel lens amplified the light so it could be seen almost 30 miles away. Keepers who lived on the cape first lit the lamp with whale oil and then kerosene until electricity finally arrived. The lighthouse warns ships about the dangerous Cape Lookout Shoals, sandbars that jut out over 10 miles into the ocean. Its diagonal checker pattern was added in 1873 as a unique daymark so mariners could distinguish it during the day, just as they use light flash patterns to distinguish lighthouses at night.