Between the Queen’s Diamond Jubilee in June and the Olympics in July and August, this summer belongs to London—and hotels are gearing up. Bulgari Hotel & Residences (from $950; 171 Knightsbridge; 44-20/7151-1010) will open its first property here on May 28. Firmdale Hotels adds a Marylebone gem to its boutique mix—the 38-room Dorset Square Hotel (from $250; 39–40 Dorset Sq.; 44-20/7723-7874) opens June 18. The Central Weekend of the queen’s revelry (June 2–5) is packed with historic events. The Thames Diamond Jubilee Pageant on June 3 promises to be a sight, with the queen’s barge leading more than a thousand boats. And on June 4, just weeks before the July 27 opening ceremonies of the Summer Olympics, Britons will light more than 4,000 torches—or, in Britspeak, “beacons”—in celebration of the queen.