How "overtourism" can strain popular tourist destinations Cities and attractions across the globe are experiencing severe overcrowding and other stresses brought on by too many tourists. According to the United Nations' World Tourism Organization, there were around 70 million international tourist arrivals back in 1960. Today, that number has hit more than 1.4 billion. Erin Florio, travel news director for Conde Nast Traveler, joins "CBS This Morning" to discuss the impact of all that tourist traffic.