The quality of life in any country significantly drops when personal safety is at risk.
This is whether it is living somewhere that is rife with crime, to being under threat of terrorist acts.
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.
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It looked at data for the whole of 2015 so any recent terrorist attacks in Europe have not been accounted for. These will be taken into consideration for next year's ranking.
However, 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.
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 12 most unsafe cities in Europe:
12. Paris — The city ranked 71st after a series of terrorist attacks. In November last year, 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.
T=7. 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.
T=7. 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.