According to a new study based on Mexico, 45 of them are located on the American continent, with 40 on Latin America, 4 in the US and 1 in Jamaica.
Five of the 10 most violent cities in the world are Mexican. 45 of the 50 most violent cities are located in the Americas and 40 in Latin America. The most violent subnational jurisdiction in the world for Honduras and 3 of the 10 most violent sub-national jurisdictions in the world are Honduran. 19 of the 50 jurisdictions world's most violent are located in Mexico and Central America. In Mexico, followed by "shaving" the numbers to pretend that there is less violence.
With a rate of 159 intentional homicides per 100 thousand inhabitants, the Honduran city of San Pedro Sula was the world's most violent city in 2011.
With a rate of 159 intentional homicides per 100 thousand inhabitants, the Honduran city of San Pedro Sula was the world's most violent city in 2011.
(Full study).
http://translate.google.com/translate?sl=auto&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&u=http://www.seguridadjusticiaypaz.org.mx/sala-de-prensa/541-san-pedro-sula-la-ciudad-mas-violenta-del-mundo-juarez-la-segunda
The number of cities on the index by country is as follows: 14 Brazil, 12 Mexico, 5 Colombia, 4 (It said 5 not on Latin America, but I think the last one is in Jamaica) United States, 4 South Africa, 3 Venezuela, 2 Honduras, 1 Jamaica, 1 Guatemala, 1 El Salvador, 1 Panama, 1 Iraq.
Edit: You can find the following table in a cleaner way in the above link.
Position City Country Homicide People Rate
1 San Pedro Sula Honduras 1.143 719.447 158.87
2 Juarez Mexico 1.974 1,335,890 147.77
3 Maceió Brazil 1.564 1,156,278 135.26
4 Acapulco Mexico 1.029 804.412 127.92
5 Central District Honduras 1.123 1,126,534 99.69
6 Caracas Venezuela 3.164 3,205,463 98.71
7 Torreón (metropolitan) Mexico 990 1,128,152 87.75
8 Chihuahua Mexico 690 831.693 82.96
9 Durango Mexico 474 593.389 79.88
10 Belém Brazil 1.639 2,100,319 78.04
11 Cali Colombia 1.720 2,207,994 77.90
12 Guatemala Guatemala 2.248 3,014,060 74.58
13 Culiacan Mexico 649 871.620 74.46
14 Medellin Colombia 1.624 2,309,446 70.32
15 Mazatlan Mexico 307 445.343 68.94
16 Tepic (metropolitan area) Mexico 299 439.362 68.05
17 Vitoria Brazil 1.143 1,685,384 67.82
18 Veracruz Mexico 418 697.414 59.94
19 Ciudad Guayana Venezuela 554 940.477 58.91
20 San Salvador El Salvador 1.343 2,290,790 58.63
21 New Orleans United States 199 343.829 57.88
22 Salvador (and RMS) Brazil 2.037 3,574,804 56.98
23 Cucuta Colombia 335 597.385 56.08
24 Barquisimeto Venezuela 621 1,120,718 55.41
25 San Juan Puerto Rico 225 427.789 52.60
26 Manaus Brazil 1.079 2,106,866 51.21
27 São Luís Brazil 516 1,014,837 50.85
28 Nuevo Laredo Mexico 191 389.674 49.02
29 João Pessoa Brazil 583 1,198,675 48.64
30 Detroit United States 346 713.777 48.47
31 Cuiabá Brazil 403 834.060 48.32
32 Recife Brazil 1.793 3,717,640 48.23
33 Kingston (metropolitan) Jamaica 550 1,169,808 47.02
34 Cape Town South Africa 1.614 3,497,097 46.15
35 Pereira Colombia 177 383.623 46.14
36 Macapá Brazil 225 499.116 45.08
37 Fortress Brazil 1.514 3,529,138 42.90
38 Monterrey (metropolitan area) Mexico 1.680 4,160,339 40.38
39 Curitiba Brazil 720 1,890,272 38.09
40 Goiânia Brazil 484 1,302,001 37.17
41 Nelson Mandela Bay Metropolitan Municipality (Port Elizabeth) South Africa 381 1,050,930 36.25
42 Barranquilla Colombia 424 1,182,493 35.86
43 ST. Louis United States 113 319.294 35.39
44 Mosul Iraq 636 1,800,000 35.33
45 Belo Horizonte Brazil 1.680 4,883,721 34.40
46 Panama Panama 543 1,713,070 31.70
47 Cuernavaca (metropolitan area) Mexico 198 630.174 31.42
48 Baltimore United States 195 620.961 31.40
49 Durban South Africa 1.059 3,468,087 30.54
50 City of Johannesburg South Africa 1.186 3,888,180 30.50
1 San Pedro Sula Honduras 1.143 719.447 158.87
2 Juarez Mexico 1.974 1,335,890 147.77
3 Maceió Brazil 1.564 1,156,278 135.26
4 Acapulco Mexico 1.029 804.412 127.92
5 Central District Honduras 1.123 1,126,534 99.69
6 Caracas Venezuela 3.164 3,205,463 98.71
7 Torreón (metropolitan) Mexico 990 1,128,152 87.75
8 Chihuahua Mexico 690 831.693 82.96
9 Durango Mexico 474 593.389 79.88
10 Belém Brazil 1.639 2,100,319 78.04
11 Cali Colombia 1.720 2,207,994 77.90
12 Guatemala Guatemala 2.248 3,014,060 74.58
13 Culiacan Mexico 649 871.620 74.46
14 Medellin Colombia 1.624 2,309,446 70.32
15 Mazatlan Mexico 307 445.343 68.94
16 Tepic (metropolitan area) Mexico 299 439.362 68.05
17 Vitoria Brazil 1.143 1,685,384 67.82
18 Veracruz Mexico 418 697.414 59.94
19 Ciudad Guayana Venezuela 554 940.477 58.91
20 San Salvador El Salvador 1.343 2,290,790 58.63
21 New Orleans United States 199 343.829 57.88
22 Salvador (and RMS) Brazil 2.037 3,574,804 56.98
23 Cucuta Colombia 335 597.385 56.08
24 Barquisimeto Venezuela 621 1,120,718 55.41
25 San Juan Puerto Rico 225 427.789 52.60
26 Manaus Brazil 1.079 2,106,866 51.21
27 São Luís Brazil 516 1,014,837 50.85
28 Nuevo Laredo Mexico 191 389.674 49.02
29 João Pessoa Brazil 583 1,198,675 48.64
30 Detroit United States 346 713.777 48.47
31 Cuiabá Brazil 403 834.060 48.32
32 Recife Brazil 1.793 3,717,640 48.23
33 Kingston (metropolitan) Jamaica 550 1,169,808 47.02
34 Cape Town South Africa 1.614 3,497,097 46.15
35 Pereira Colombia 177 383.623 46.14
36 Macapá Brazil 225 499.116 45.08
37 Fortress Brazil 1.514 3,529,138 42.90
38 Monterrey (metropolitan area) Mexico 1.680 4,160,339 40.38
39 Curitiba Brazil 720 1,890,272 38.09
40 Goiânia Brazil 484 1,302,001 37.17
41 Nelson Mandela Bay Metropolitan Municipality (Port Elizabeth) South Africa 381 1,050,930 36.25
42 Barranquilla Colombia 424 1,182,493 35.86
43 ST. Louis United States 113 319.294 35.39
44 Mosul Iraq 636 1,800,000 35.33
45 Belo Horizonte Brazil 1.680 4,883,721 34.40
46 Panama Panama 543 1,713,070 31.70
47 Cuernavaca (metropolitan area) Mexico 198 630.174 31.42
48 Baltimore United States 195 620.961 31.40
49 Durban South Africa 1.059 3,468,087 30.54
50 City of Johannesburg South Africa 1.186 3,888,180 30.50
For context, New York had a murder rate of 4.5 per 100.000 in 2010.
http://www.disastercenter.com/crime/nycrime.htm
It's clear that Latin America is by far the most violent region in the world, but why?
The drug trade is surely part of the answer, but there are parts of the world that are poorer and less developed than Latin America, likes most of Africa and parts of Asia, that still don't show such levels of violence, so maybe there's a cultural element at play?