Alex Robertson sheds some light on a famous English landmark.
Majestically rising 31 metres over the Suffolk town of Southwold on England's east coast, the Southwold Lighthouse has been a landmark and a beacon for shipping for more than 100 years.
It's hard to believe that the light, visible more than 30km out to sea, comes from two 12-volt halogen lamps.
I'd climbed the 133 steps that cling to the inside wall of the lighthouse to learn this fact one sunny day in September. The British summer had been kind and the power of the lights had not really been tested for months.
But winter was fast approaching, and the ships on the horizon seemed to be waiting for a signal to come in and mind the rocks ... although our guide said the owners were studying commodity prices, looking for upward movement before sending their vessels into port.
As an island nation, Britain has relied on shipping for trade, growing wealthy from East Anglian sheep in Elizabethan times, the colour and richness of the subcontinent and the treasures brought home in the 17th and 18th centuries, commodities from the colonies of the New World in the 19th and 20th.
As trade grew, so did the Royal Navy to protect its merchant fleet, and Britannia ruled the waves.
But British ships still faced mortal danger in and around the coastal waterways from rocks, cliffs and sandbanks.
The first lighthouse to be built was at Lowestoft, a few kilometres north of Southwold, in 1609. It survived by charging a levy on all ships that visited the port.
Lights and beacons sprung up all over the British Isles in the ensuing centuries. When Southwold Lighthouse appeared in 1890, Trinity House had been in charge of all lights around the British coast since 1836 to maintain reliability and standards.
The odd thing about lighthouses is that they're round. As I stood (with seven other visitors and our guide) in the room where two lighthouse keepers once went about their daily chores, I kept thinking of jokes about Irishmen and corners.
Why are they round? Apparently, because of their coastal position, lighthouses are battered by strong winds and the round shape helps deflect the windpower.
They're also high up - for more obvious reasons - so the keepers spent every night 30 metres in the air in a room the size of a generous lift pumping oil to power the lamp (first whale oil, then, from 1902, mineral oil) before electricity reached Southwold and the lighthouse in 1938.
Now the light is powered by a huge bank of car batteries which are more reliable than mains electricity and the system is automated - more redundancies.
Twice a year, the lead crystal glass lens, installed in the 1890s, is cleaned. The 12-volt lamps are attended to a little more often.
I gazed out to sea, to the ships on the horizon wondering if their crews felt safe knowing that their safety rested on nothing more than a car headlamp.
Southwold Lighthouse is open to visitors for two hours on three days per week between May and October. The 20-minute tour costs £3 (NZ$6). See trinityhouse.co.uk for details.
Alex Robertson paid his own way to Southwold.