In tonight's rail journey programme from Vienna to Trieste he goes down the Lurgrotte - scene of a rescue over 100 years ago.

The caving bit comes at 4mins 30 for those wishing to go express as it were.

oops - link https://www.bbc.co.uk/iplayer/episode/b08gdt5m/great-continental-railway-journeys-series-4-reversions-4-vienna-to-trieste-part-2

It doesn't come close to David Davis and David Rutley's trip down Bar Pot!

True - the "caving" was trivial but the story of the mega-rescue was interesting. 20,000 rescuers, new entrance/exit created, huge dam constructed in the flood; all over 100 years ago - wow.