#16
At the Royal Observatory, Greenwich, time and place snap into focus. Stand astride the Prime Meridian, marked in 1851 and adopted worldwide in 1884, then meet Harrison's chronometers that solved longitude at sea. Flamsteed House frames London, while the 28-inch Great Equatorial Telescope broods under its green dome. Outside, the red time ball drops at one o'clock, a nineteenth-century signal still working. Planetarium shows add a cosmic coda. The hill is steep but rewarding; bring comfortable shoes and a camera for sunset across the Thames. Book a timed slot, allow 90-120 minutes, and fold in the Cutty Sark for a perfect Greenwich double.
