Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch (St Mary's Church in the Hollow of the White Hazel near a Rapid Whirlpool and the Church of St. Tysilio near the Red Cave) is a village on the island of Anglesey, in Wales which has the longest name in the United Kingdom and the third-longest in the world. For most purposes, however, the name is abbreviated to Llanfair PG (or Llanfairpwll among Welsh speakers) which is sufficient to distinguish it from other Welsh places named Llanfair. It is a popular tourist destination, many people stopping at the railway station to have their photos taken next to the station sign, visiting the nearby Visitors' Centre or having their passports stamped at a local shop. Another tourist attraction is the nearby Marquis of Anglesey's Column, giving views over Anglesey and the Menai Straits.
The name was contrived in the 1860s by the village council, specifically for the privilege and prestige of having "the longest name of a railway station in Great Britain". It could not be considered an authentic word from Welsh. In fact, the original name of the place was Llanfair Pwllgwyngyll, which itself is respectably long (though only having 16 letters in the Welsh alphabet as opposed to 19 in English).
A reasonable attempt at a pronunciation would be Clan vire pulth gwinn gith gor gerrick win drob uth clan tay see lee oh go go gogch. (The "gch" in the final syllable is the "glottal h" sound, similar to the sound used in the Yiddish "l'chaim". Saying gok glottally produces more or less the same effect.) Two lls can be pronounced either as 'cl' or 'l', or more precisely as an 'l', while passing air around the tongue (try blowing while saying "l").