I stumbled upon a few web sites that offer touring services historical cities by joining the offer by local guides, agencies and privates. One site, www.getyourguide.com , based in Switzerland, has an on-line booking and payment system and definitely has a quite substantial offer: there are more than 700 tours offered in Italy (nearly 200 in Rome alone). In Europe, Italy has by far the largest offer on the site. Spain, Germany and France offer around 300 tours, followed by the United Kingdom, Turkey, Portugal, Austria and Greece. The biggest offer comes from the USA with more than 900 tours offered. Pricing varies depending on the offer but tends to be relatively aligned: for a 3 hours in the Vatican Museums and Church the cost per person is around 30 to 40 euros (tickets not included). The site is organized like any travel booking site with as much services and content available on the home page, but it is still easy to find your way. The upper part of the site is occu...