Old Royal Observatory, Greenwich, UNESCO World Heritage Site, London SE10, England, United Kingdom, Europe

GMT clock and standards of length, Flamsteed House, Greenwich, UNESCO World Heritage Site, London, England, United Kingdom, Europe

The original Royal Observatory dating from 1675 and site of the Prime Meridien (latitude 00, starting point of Greenwich Mean Time, Greenwich Park, Greenwich, London, England, United Kingdom, Europe

The original Royal Observatory dating from 1675 and site of the Prime Meridien (latitude 00, starting point of Greenwich Mean Time, Greenwich Park, Greenwich, London, England, United Kingdom, Europe

Greenwich Mean Time Clock, Royal Observatory, UNESCO World Heritage Site, Greenwich, London, England, United Kingdom, Europe

The Shepherd 24-hour gate clock at the Royal Observatory, Greenwich, UNESCO World Heritage Site, London, England, United Kingdom, Europe

The Shepherd 24-hour gate clock at the Royal Observatory, Greenwich, UNESCO World Heritage Site, London, England, United Kingdom, Europe

Meridian Line, Royal Observatory Greenwich, London, England, United Kingdom, Europe