Personal safety is one of the key components for living somewhere with a decent quality of life.
And so Mercer, one of the world's largest HR consultancy firms, releases its Quality of Living Index each year, part of which ranks the safest cities to live and work in.
The list is one of the most comprehensive of its kind and is carried out annually to help multinational companies and other employers to compensate employees fairly when placing them on international assignments, according to Mercer.
The 30 most dangerous cities in the world
The 30 most dangerous cities in the world
1/30 30. Teresina, Brazil
Teresina had 42.64 homicides per 100,000 residents. According to the Mexico Citizens Council for Public Security's annual ranking of the world's most violent cities in 2015)
2/30 29. Goiânia y Aparecida de Goiânia, Brazil
Goiânia has 43.38 homicides per 100,000 residents
3/30 28. Detroit, Michigan, USA
Detroit had 43.89 homicides per 100,000 residents
4/30 27. Feira de Santana, Brazil
Feira de Santana had 45.5 homicides per 100,000 residents.
5/30 26. Belém, Brazil
Belém had 45.83 homicides per 100,000 residents
6/30 25. Guatemala City, Guatemala
Guatemala had 47.17 homicides per 100,000 residents.
7/30 24. Cumaná, Venezuela
Cumaná had 47.77 homicides per 100,000 residents
8/30 23. Manaus, Brazil
Manaus had 47.87 homicides per 100,000 residents
9/30 22. Cuiabá, Brazil
Cuiabá had 48.52 homicides per 100,000 residents
10/30 21. São Luís, Brazil
São Luís had 53.05 homicides per 100,000 residents
11/30 20. Barquisimeto, Venezuela
Barquisimeto had 54.96 homicides per 100,000 residents
12/30 19. Baltimore, Maryland, USA
Baltimore had 54.98 homicides per 100,000 residents
13/30 18. Maceio, Brazil
Maceio had 55.63 homicides per 100,000 residents.
14/30 17. Culiacan, Mexico
Culiacan had 56.09 homicides per 100,000 residents
15/30 16. João Pessoa, Brazil
João Pessoa had 58.40 homicides per 100,000 residents
16/30 15. St. Louis, Missouri, USA
St. Louis had 59.23 homicides per 100,000 residents
17/30 14. Salvador, Brazil
Salvador had 60.63 homicides per 100,000 residents
18/30 13. Natal, Brazil
Natal had 60.66 homicides per 100,000 residents
19/30 12. Fortaleza, Brazil
Fortaleza had 60.77 homicides per 100,000 residents
20/30 11. Ciudad Guayana, Venezuela
Ciudad Guayana had 62.33 homicides per 100,000 residents
21/30 10. Cali, Colombia
Cali had 64.27 homicides per 100,000 residents
22/30 9. Cape Town, South Africa
Cape Town had 65.53 homicides per 100,000 residents
23/30 8. Palmira, Colombia
Palmira had 70.88 homicides per 100,000 residents
24/30 7. Valencia, Venezuela
Valencia had 72.31 homicides per 100,000 residents
25/30 6. Distrito Central, Honduras
Distrito Central had 73.51 homicides per 100,000 residents.
26/30 5. Maturin, Venezuela
Maturin had 86.45 homicides per 100,000 residents
27/30 4. Acapulco, Mexico
Acapulco had 104.73 homicides per 100,000 resident
28/30 3. San Salvador, El Salvador
San Salvador had 108.54 homicides per 100,000 residents
29/30 2. San Pedro Sula, Honduras
San Pedro Sula had 111.03 homicides per 100,000 residents
30/30 1. Caracas, Venezuela
Caracas had 119.87 homicides per 100,000 residents
Mercer says the personal-safety ranking is based on the cities' "relationship with other countries, internal stability, crime, and law enforcement." In other words, it should come as no surprise that war-torn cities or those rife with crime rank the lowest.
Mercer looked at 450 cities and then made a list of 230 cities that are the safest for workers. While a host of European cities are listed as being among the safest in the world, others surprisingly rank very low in the index.
This may come as a surprise that some of Western Europe's biggest and most affluent cities are not leading the list for being the safest cities on earth but this is mainly due to a number of terrorist attacks and threats over the last year that have dragged them down the rankings.
Other issues like petty crime or threats to national security have also made an impact on some of the cities.
Business Insider went to the bottom of the list to find the 17 most unsafe cities in Europe.
17. Milan — The city slipped in the ranking to No. 63 this year after the FBI warned that St. Peter's Basilica, the Duomo, and La Scala were under threat of a terrorist attack.
15 (tie). Barcelona, Spain — The city is known for being one of the pickpocket capitals of the world, pushing it into rank 64th on the personal-safety index. The British foreign office says under the safety and security section (crime) "there has been an increase in the number of thefts from hire cars; remove all valuables or store items out of sight."
15 (tie). Belfast, Northern Ireland — The city, ranked 64th, has a relatively low violent crime rate compared with other towns and cities in Northern Ireland. But the proportion of people living in poverty is the highest in Belfast, rocking social stability and increasing petty crime.
13 (tie). Tallinn, Estonia — The picturesque walled city has relatively low violent crime but ranked 66th in the list because of drug and human trafficking from organised Russian syndicates.
13 (tie). Warsaw, Poland —The city has one of the lowest crime rates in the country but ranked 66th because of the number of political protests being held in Poland.
12. Paris — The city ranked 71st after a series of terrorist attacks. In November, suicide bombers and gunmen attacked multiple locations in France's capital, including cafés, restaurants, and a music venue, killing 130 people and injuring hundreds of others.
11. London — It may be a surprise to see London in the list, but Mercer ranked Britain's capital 72nd. Ellyn Karetnick, head of Mercer's International Mobility Practice in the UK, said, "In Europe and beyond terrorist attacks and incidences of civil unrest are closely monitored and analysed, and any impact on quality of living for expatriates is reflected in the rankings."
10. Bucharest, Romania — Violent and organised crime is quite low in Romania's capital, but the city ranked 79th because of widespread corruption and petty crime.
9. Zagreb, Croatia —Like Zagreb's other major Eastern European counterparts, corruption drags the city down — it ranked 79th.
7 (tie). Riga, Latvia — Apart from anti-immigration protests starting to dominate the streets, Riga is ranked 82nd on the index for its thriving organised crime and prostitution syndicates.
7 (tie). Rome — The city dropped to 82nd after Rome, and other Italian cities, were put on high alert for terrorist attacks similar to the Paris attacks in November.
6. Madrid — The city ranked 84th in Mercer's list for its social unrest resulting from countrywide austerity measures that led to massive unemployment levels, especially among its youth population.
5. Budapest, Hungary — The city dropped to 93rd in the index after a massive increase in social unrest in the city since the refugee crisis. Chaos at train stations and protests in the streets have erupted several times as Hungarian Prime Minister Viktor Orban has tried to curb the flow of migrants in and through the country.
4. Sofia, Bulgaria — A high level of social unrest has pushed the city into 118th. People in Bulgaria, which is the European Union's poorest member, continually protest against the government over benefit and pension cuts as well as against corruption.
3. Athens, Greece — After extensive and prolonged austerity measures, poverty and crime has increased giving Athens a ranking of 124. Furthermore, "the recent political and economic turmoil in Greece, which resulted in violent demonstrations in Athens and other cities in the country, has undermined its safety ranking," says Mercer. The influx of hundreds of thousands of migrants is also exacerbating the city's safety position.
2. Belgrade, Serbia — Violent crimes are low in the city, but Belgrade sinks to 131st in the index for its wide-scale corruption and bribery issues as well as from theft and vandalism.
1. Kiev, Ukraine — The country's capital ranks 189th because of civil unrest and its pugilistic relationship with Russia. Though the UK foreign office says Kiev is "calm" compared with the Russian-annexed region of Crimea, Kiev is rife with theft, vandalism, and violent protests that have killed or injured hundreds of people.