Christmas in London is something special. The city fills with enormous Christmas trees, glowing shop windows, traditional markets, outdoor ice rinks, festive shows, and some of the most recognizable Christmas lights in the world. New York City sets a very high bar for Christmas destinations, but London belongs on the same shortlist. Regent Street’s illuminated angels, the decorations around Covent Garden, and the markets beside the Thames make even an ordinary walk through the city feel festive. London’s Christmas season generally begins in early to mid-November and continues into the first days of January. That gives you plenty of...