Safety's a big part of what makes a country appealing for visitors: history and culture are all well and good, but if you're risking your life by getting off the plane, it kinda detracts from the experience.
Luckily, the Institute for Economics & Peace compiles an annual "Global Peace Index" report that ranks 162 of the world's nations on their safety and peacefulness. The GPI factors "23 qualitative and quantitative indicators" into its ranking, ranging from violent crime levels and political terror to weapons imports/exports and prison population, and assigns each nation a score of 1-5, with 1 being the highest.
Iceland took first place this year with a near-perfect score of 1.148, while Denmark grabbed second (1.150) and Austria landed in third (1.198). The United States actually scored a comically bad 2.038, which brought it all the way down to 94th place -- above Saudi Arabia, but below Peru.