Is tourism a scourge? Critics say too many people want to travel and they are destroying the places they are meant to protect. Others argue the world would be poorer without them.
UK tourist faces jail for Colosseum carving
Ivan the terrible tourist? The sightseer wrote a letter of apology to Rome's mayor. Glossary
UNESCO - The United Nations Educational, Scientific and Cultural Organisation. It aims to promote international cooperation in the arts, education, science and culture.
Machu Picchu - An Inca city built in the Andes mountains in the 15th Century and then abandoned.