It took 6 months for the plan to come together - Talking to contacts on the internet to get the maps and discover access details, rearranging diaries, booking travel and ordering equipment but the Paris Catacombs are, for me at least, the holy grail of European exploration....
4 Days in The Grand Réseau Sud - Les Catacombes de Paris - October 2016
4 Days in The Grand Réseau Sud - Les Catacombes de Paris - October 2016