Tourists often cause environmental damage, with things like pollution and forest fires. Even if tourists behave responsibly, the sheer number of the them can cause problems. Things like ancient buildings, monuments and temples often struggle to cope with the vast amounts of tourist traffic and suffer wear and tear, or damage.
The commercialization of culture can undermine the soul of a tourist destination. Local traditions that have a rich cultural heritage are reduced to wearing costumes and putting on acts for the tourists in return for money.