About 54 percent of the world's population lives in cities; by 2050, the United Nations estimates that figure will reach 66 percent.
Some cities are, of course, safer than others. The Economist recently ranked 50 world cities in four categories -- personal security, health security, infrastructure safety, and digital security -- to find which are the safest. Here are the top ten safest cities in the world, according to The Economists's Safe Cities Index:
10. New York City
9. Melbourne, Australia
8. Toronto
7. Zurich
6. Sydney
5. Amsterdam
4. Stockholm
3. Osaka, Japan
2. Singapore
1. Tokyo (pictured)
Source: The Economist Intelligence Unit's Safe Cities Index 2015