Tourism has become a global phenomenon due to various factors. International tourism arrivals have increased nearly 1 billion from 1950 to 2010 as countries experienced economic growth and improvements in transportation. While Europe was previously the most visited region, Asia Pacific has overtaken North and South America to be the second most visited region since the 2000s. Tourism has also evolved from mass tourism to include niche tourism like ecotourism. However, tourism is subject to regional fluctuations due to disasters, economic recessions, political instability, or disease outbreaks, which can negatively impact tourist arrivals in affected regions.