Philly is bad but let's compare best to best and worst to worst. What is the US state or county with lowest homicide rate? Higher than Norway probably, but by how much? What is the worst in Europe?
The worst in Europe are the Baltic states. Latvia and Lithuania would be equivalent to middle of the pack US states. Outside the Baltic states, the rest of the EU and UK would be, at worst, just nudging the bottom of the states' rankings or, at best, quite some way below.
Once you get to Turkey and the Balkan states, you are again nudging lowish US numbers. BTW the reason Liechtenstein is an outlier is because it has a population of 38k. So this suggest that one person was murdered there in 2018.
[0] https://ec.europa.eu/eurostat/statistics-explained/index.php...
[1]https://en.wikipedia.org/wiki/List_of_U.S._states_and_territ...
The ones with cold winters and minimal urbanization.
https://en.wikipedia.org/wiki/List_of_United_States_cities_b...