Traveling is fun, but it can be risky. In many countries of the world, rates of crime and communicable disease can be much higher than in most countries of Europe and the Anglosphere.
Kidnappings, dangerous infections, corrupt law enforcement, and much more. Brush up on the risks before you go.
Travel risk ratings of most dangerous destinations from Harvard
Russia and many nations of Africa, Asia, and Central/South America display highest levels of travel risk.
Kidnapping Risk:

Global Kidnapping Risk
PDF Map File
https://www.red24.com/pdf/red24_Special_Risks_-_Global_Kidnapping_Threat_Map_2017.pdf
Violent Crime/Homicide Risk:
Communicable Disease Risk:

Most Common Infectious Disease by Country
https://www.pri.org/stories/2014-10-27/map-shows-which-deadliest-infectious-disease-where-you-live
Public Health/Health Care Infrastructure by Nation:
Recent changes? Very little change between the 2016 travel risk map at top and the 2018 map below:
Travel Risk and Poverty Correlated
The most dangerous travel destinations are generally more impoverished and corrupt, and tend to display much lower levels of economic freedom.
Economic Freedom:
Per Capita GDP:

IMF Map via Reddit
In general it is safer to travel to countries that can afford internal stability. Most governments of third world and emerging nations are too busy bleeding their people dry and enforcing dictatorial powers, to pay attention to the basics that would allow their people to live in safety and prosperity — and make the world safer for travelers.
Why Are Some Nations Rich and Others Poor?
You can sum it up in a few phrases: Bad government, rotten cultures, stupid people. Avoid those things — or keep them to a minimum — and you will promote safety, prosperity, and stability.
Read these books for more information: