6. Raf Stenigot: England
Built during World War II as a radar station, the RAF Stenigot station was part of a network called the Chain Home radar network, design to warn the RAF of air raids. After the war, it served as a communications relay site until it fell into disrepair. In the 1980s, the British decommissioned the site. By 1996, most of it fell to demolition crews. What remains is a memorial.