The Barbican Conservatory is a tropical garden hidden inside the concrete bulk of the Barbican Centre. It holds more than 2,000 species of plants, with palms, vines, fish pools, and small corners of dense greenery set against the estate's Brutalist walkways.
It is one of the stranger quiet escapes in central London. Opening times are limited and often tied to weekends or booked slots, so check before crossing town.