The undisputed king of atlas online travel is Google. It’s free, easy to use, a robust database, directions, street view, different map types, save & shareable maps, and they’re slowing integrating travel booking into it.
Depending on what you need, you might look elsewhere. If you will drop a lot of pins, you’ll have to use “layers” since Google limits you to 10/layer. If you’re looking for a map to represent data, like a heat map, a travel map, or an animated map, Google isn’t going to be your solution.