Northernmost inhabited British Isle in Shetland, 46 sq mi
Shetland Islands Council has backed a plan to explore four subsea tunnels, linking Mainland with Yell and Unst, with later links to Bressay and Whalsay. The project aims to replace aging ferries and unlock economic growth, with an estimated total cost of about 1.5 billion pounds and a completion timeline of eight years for the first tunnel.