London

The London Underground, opened in 1863 as the world's first metro system, still carries the marks of its age — some of the deepest, oldest tunnels on the network were bored to a diameter that physically can't accommodate the larger trains used elsewhere, which is why certain lines still run noticeably smaller carriages than others. It's a genuinely strange piece of infrastructure history hiding in plain sight for anyone riding the Central or Bakerloo lines.

London's major museums operate on a model that's rare among world capitals: general admission to the British Museum, National Gallery, Tate Modern, and Natural History Museum is free, a policy dating back to a 19th-century belief that culture shouldn't be gated by wealth, still intact today. The British Museum specifically houses the Rosetta Stone and the Parthenon Marbles — the latter a genuine, ongoing diplomatic dispute with Greece over where they should permanently reside, similar to the conversation happening around the Acropolis Museum in Athens.

The city's markets serve different purposes and shouldn't be treated as interchangeable. Borough Market, tucked under London Bridge, is a serious food market — good for an actual meal from vendors doing one thing well rather than a browsing experience. Camden Market, further north, is larger and leans harder into alternative fashion, vintage, and general stall culture, better suited to an afternoon of wandering than a specific culinary stop.

Theatre is one of London's genuine cultural exports, and the West End runs a repertoire distinct from Broadway — some shows overlap, but plenty of major productions premiere in London first or never transfer at all. Same-day discounted tickets are available at the TKTS booth in Leicester Square for visitors willing to be flexible about which show.

London is expensive relative to most of the destinations in this guide, particularly on accommodation and dining, though the free-museum model does real work offsetting that for anyone spending most of a day inside them rather than at paid attractions. Public transit, using a contactless card rather than paper tickets, is comparatively reasonable and covers the entire city efficiently despite its age and sprawl.