European homicide rates?

I'm curious to know why U.S. cities have far more murders than European cities. Any thoughts? I know poverty exists everywhere, but looking at the stats, I see troubled cities like Glasgow Scottland was the worst with about 5.5 murders/100k people while US cities like New Orleans or Detriot are around 50-60 murders/100k. I'm from Minneapolis, Minnesota. It has a murder rate of about 15-17 per 100,000 which isn't even considered bad. Is it the availaibity of guns, more poverty or what? I'm just curious on ur thoughts. THANKS!