var course = document.querySelector(".course");
var courseClass = course.className;
var locations = [
"Berlin", "Munich", "London"
];

function addLocations () {
    for(var i = 0; i < locations.length; i++) {
        if (courseClass.includes(locations[i])) {
            course.innerHTML = `<h1>${locations[i]}</h1>`
        }
    }
}

addLocations();