388 Lambeth Walk? LONDON TRANSPORT plays the continuous role of host to visitors from all over the world. The year round, and especially in summer, these friendly strangers come to London to turn for themselves the pages of its history and to find those sights, pleasures and interests which no other city can offer. Because London is as diverse as it is large, our visitors ask many questions. "When is the Guard changed in Whitehall?" It is at 11.0 a.m. on weekdays and 10.0 a.m. on Sundays. "Can we actually see the Crown Jewels?" Certainly: at the Tower of London, and they may now be seen on weekdays between 10.