World's Most Secret Hotels

This episode explores Bolivia's Salar de Uyuni, a striking brutalist lodge seamlessly blending in with the edge of the world's largest salt flat. It also features a futuristic getaway of bubble domes in County Fermanagh in Northern Ireland, a mirrored resort overlooking a majestic Norwegian fjord, an art deco hotel nestles amid the Pyrenees, and the extra-terrestrial-inspired design of a unique homestay in Wales.

Visits to a fortress-style hotel in the Empty Quarter in the United Arab Emirates, a minimalist hotel on the tranquil banks of a Norwegian river, a futuristic fantasy with three bespoke treehouses in Dorset woodland, an eco-friendly yellow submarine on the river banks of County Monaghan in Ireland, and a luxury hotel fashioned from repurposed shipping containers in the New South Wales Australian outback.

An old Cornwall jail becomes an extraordinary luxury retreat, and opulent ancient caves bring the South African wilderness up close. A historic Swedish lighthouse on the rugged rocks of Paternoster Island shines a light for luxury seekers, while in tropical northern Queensland, an eco-resort offers stunning treetop accommodation.