Tell a Londoner you are heading to Cardiff for the weekend and the response will probably be a quizzically arched eyebrow. The Welsh capital, which was largely built during Britain’s 19th-century coal boom, isn’t generally considered one of the country’s most attractive cities. But times are changing. Major regeneration projects since the 1990s — a new performing arts center, a revamped waterfront and a 74,000-seat stadium, to name a few — have given the city a fresh face. Don’t worry, though, Cardiff still has its edge: the punk rock scene is as vibrant as ever, and Welsh rugby fans have never cheered louder.