Buying a train ticket home should not require an 18-syllable word, but for residents of one village on the Isle of Anglesey it is simply their address. This episode looks past the famous 58-character railway sign to uncover the 4,000-year history of Llanfairpwllgwyngyll, from Neolithic settlers who built a dolmen at Ty Mawr, to the Roman commander Suetonius Paulinus who stormed the island to crush the Druids and then abandoned it to fight Boudica, to medieval tenants farming nine bovates of land under the Bishop of Bangor.

The heart of the story is the 19th century, when land enclosures, Thomas Telford’s Menai Suspension Bridge, and the Britannia railway bridge ended the village’s isolation and threatened to send trains straight past it toward Holyhead. The response was a marketing masterstroke: stuffing every local landmark into one enormous name, from the pool of the white hazels to the fierce whirlpool and the red cave. The episode weighs the legend of a local tailor against 1849 and 1866 records that show the long form already in use, then follows the name into Barbarella, a Stephen Sondheim song, a Guinness-record crossword clue, a Super Furry Animals EP, Helldivers 2, and even a newly discovered soil bacterium.

• Why the original name, the Pool of the White Hazels, was perfectly adequate for centuries
• How 92 percent of village land came to be owned by three people by 1844
• The case for treating the name as Victorian search engine optimization
• A town of about 2,900 people, 71 percent Welsh-speaking, that draws 200,000 visitors a year
• The village’s real history as home of the first Women’s Institute meeting in Britain and painter Kyffin Williams