Peru's mysterious past inspires a childlike fascination in all travelers, regardless of age, and children from seven or eight upwards - old enough to appreciate the history and the myth - will be fascinated by its ruins, folklore and gory stories. Machu Picchu is open to all, as trains allow families to bypass the hikes, and the Andean dry season coincides with school summer vacations for European and N. American visitors, making traveling in Peru with kids even easier. There are also brilliant hikes, easy biking and adventurous kayaking to keep less culturally minded kids busy. The Latino fondness for children means they tend to be welcomed everywhere - and a community tour or homestay will leave a lasting impression on young minds.
If you want to visit the Amazon, do consult a doctor well in advance to find out which treatment will be necessary - or feasible - for young children.