The Explorer's Club is a club for explorers and adventurers. They have a number of rooms for those who mostly travel, but who want or need a place between voyages.
Full membership requires a certain number of trips to places without modern amenities.
Geoffrey Carillon is delighted that
Lizzie Penhallow was a member in her own right from the time she was 18 or so thanks to trips with her father and uncle.
The club has a vast library of navigational and other travel materials - maps, personal journals, published materials, and more. They host regular and wide-ranging lectures on topics of interest to the membership and also periodically sponsor or coordinate particular investgiations.
Geoffrey Carillon prefers their protections over
Bourne's.
The Carillons,
Cassie, and
Benton meet at this club in the epilogue of
On The Bias.