The owners of a Bulgarian passport can visit without a visa to 169 countries, according to the Henley Passport Index for the year 2018. So if you decide to go on a worldwide voyage involving all recognized countries on the planet, then only for 27 of them you have to get a special entry document.
First in the ranking is the Japanese passport that gives visa-free access to 189 countries. Among the strongest passports are these of Singapore, Germany, Sweden, Italy, South Korea, Spain, Finland and France, giving free access to 186 countries. At the bottom of the list are Afghanistan, Iran, Somalia, Syria, Pakistan and Yemen. Their subjects have visa-free access to just 30 countries.