In May 1963 a causeway linking Sanibel and Captiva to the mainland was opened, resulting in an explosion of growth. The City of Sanibel passed new restrictions on development after it was incorporated; these were challenged by developers, to no avail. Currently the only buildings on the island taller than two stories date before 1974, and there are no fast food or chain restaurants allowed on the island except a Dairy Queen and a Subway, which were on the island before the laws were enacted. A new causeway was completed in 2007; it replaced the worn out 1963 spans, which were not designed to carry heavy loads or large numbers of vehicles. The new bridge features a "flyover" span tall enough for sailboats to pass under, replacing the old bridge's bascule drawbridge span. The original bridge was demolished and its remains were sunk into the water to create artificial reefs in the Gulf of Mexico.