1. Tokyo

With a population of 13.3 million people, Tokyo is both the most populous and the safest city in the ranking. It also ranks first for digital security and in the top five for personal safety and infrastructure despite its huge population and its earthquakes. The city is relatively well off and ranks first on the Index's list of "upper-middle income cities" (with per capita gross domestic product (GDP) of between $30,000 and $50,000).

2. Singapore

Singapore ranks No. 1 in overall personal safety, according to the Index, which noted that traditional crimes like burglary and theft were at a decades-long low. Singapore has notoriously tough penalties for all crimes, including low-level offenses, which might contribute to its extremely low crime rate. At the time, the BBC also reported that Singapore had the second-lowest murder rate in the world (excluding Palau and Monaco). With violent crime under control, the local police have been targeting cybercrime. President Tony Tan Keng Yam has set out to improve digital security and, he hopes, make Singapore a "smart city." The city-state should have the funds to do that. It had the highest GDP per capita among "high income" cities (cities with more than a $50,000 per capita GDP).

3. Osaka

The Japanese city of 2.6 million ranks second in personal safety and sixth in health security. As with Tokyo, Osaka is relatively wealthy, and it ranks second for GDP per capita among upper-middle-income cities. The city ranks lower in digital security than Tokyo, as it has fewer cybersecurity teams and privacy policies.

4. Stockholm

The Swedish capital of 909,000 ranks seventh in digital security and 10th in health security. It is the only non-Asian city to rank in the top five in personal safety. As with many European countries, Sweden has universal healthcare.

5. Amsterdam

This city of 820,000 is known for its legal marijuana, but it also has amazing infrastructure that makes it one of the safest cities in the world. Amsterdam ranks fourth in infrastructure safety, a list dominated by high- and upper-middle-income cities that have reduced car accidents and pollution from traffic congestion. With its pervasive cycling culture, Amsterdam has managed to do both. The city also ranks in the top 10 for personal safety.

6. Sydney

This Australian city of 4.5 million people ranks in the top 10 for both infrastructure security and personal safety. However, Sydney lags behind in digital security and health security, in which it ranks 14th and 17th, respectively. Australia has some of the highest incidences of cybercrime in the world: Australians have become prime targets for internet fraud and identity thieves, according to the Daily Telegraph.

7. Zurich

Zurich ranks the highest in the categories of health safety and infrastructure security, with its excellent universal health coverage and well-designed transport systems. The city's wealth makes it easier to invest in urban safety: in the ranking's "high income" category of cities with per capita GDP of $50,000, Zurich ranks second behind Singapore.

8. Toronto

Toronto, the most populous city in Canada, is the best city to live in terms of safety, business environment, democracy, food security, cost of living, and livability, according to the Index. It also ranks in the top 10 in the categories of infrastructure safety and personal safety. Dubbed "Hollywood North," Toronto is the frequent setting for films and movies that are supposedly filmed in the US.

9. Melbourne

The city of 4 million has the second-safest infrastructure of the 50 cities ranked and ranks eighth in the category of personal safety. It's no coincidence that Melbourne has one of the highest life expectancies of any city in the world, at 86 years. As the report notes, "Living in a safe and healthy urban environment can make a real and measurable difference to city inhabitants." The report also found that it is the sixth-best city in the world to live in, when factors like safety and cost of living are taken into account.

10. New York City

New York is the only US city to make it into the top 10 safest cities overall, ranking second for health security and third for digital safety. The city has come a long way since 1990, when an average of six homicides occurred every day. Still, the city faces new dangers like terrorist threats and the potential of cyberwar that could shut down crucial infrastructure.