The CN Tower in Toronto, standing at 553.3 meters, held the record for the world's tallest free-standing structure for 32 years until the completion of the Burj Khalifa. Completed in 1976 by Canadian National Railways, it serves as a telecommunications and tourism hub. To ensure its stability, the tower was built with a hollow hexagonal concrete core that houses elevators and stairs. It is designed to withstand an earthquake of 8.5 on the Richter scale and winds up to 418 km/h. A unique feature of the tower is its lightning protection system; because of its height, it is struck by lightning an average of 75 times per year. Long copper strips run down the length of the tower and are connected to massive grounding rods buried deep in the earth to safely dissipate the electrical charge.