We had a wonderful time on the tour. Our guide, Helena or Elena, was knowledgable, friendly, helpful, humorous, and full of interesting information about the sites we visited. We liked the use of radios, even in our small group, because it made it easy to look around and see the ceilings, walls, windows, and walkways without having to be in front of her. We enjoyed visiting the Duomo, La Scala, a castle, but the highlight was seeing the Last Supper. The organization was amazing to see the painting: 30 people at a time can view the painting for 15 minutes. I was surprised how close we were to the painting. Our guide explained the painting had been repaired and restored over the centuries. A final restoration that lasted 21 years was unveiled in 1999, and it is breathtaking to see a 500 year old painting looking very much like Leonardo painted it. I would highly recommend Viator tours. The online booking was easy. We received timely confirmations and reminders. We found the office easily, and the yellow bus was clean and comfortable.