Escorted Tours
An escorted tour includes a professional guide, as opposed to being an independent (or self-guided) tour. Some escorted tour operators include a limited amount of time for guests to explore on their own, while others have tours that are completely escorted. Typically, just about your entire itinerary is included and planned for in an escorted tour package. You don't have to worry about what you're going to see and don't have to make reservations (for each component of the trip) with multiple tour operators - this option allows for you to just leave it to the professionals and enjoy yourself.
Depending on the tour operator, as well as on the specific tour, some tours are private (just you and your traveling companions, if you have any) while others are with other travelers that booked the same tour. In the latter case, some tour operators offer small groups (which tend to be more expensive, but also more intimate and exclusive) while some have larger groups that travel together (which provides a very social atmosphere, as you can meet many other people).
