https://www.copyright.gov/what-is-copyright/
Read up on how exactly copyright works, as soon as you fix a work in a tangible and communicable form, you have a copyright to it. Taking a nude photo of yourself gives you the exclusove copyright of that photo. Taking a tourist photo does give you copyright to that specific photo, but also doesn't necessarily supercede another existing copyright if that photo is of something else that already had a copyright.
And depending on jurisdictions, your tourist photos might not be fine. For example, in France, they have very strict privacy laws and copyright enforcement, the Eiffel Tower might be public domain, but the light installation is still under copyright. And any modern buildings designed by an architect who died within the last 70 years is still protected by copyright. And on the privacy front, accidentally taking pictures of other people even in tourist areas could actually open you up to a lawsuit, but nobody's actually tried that yet so it's up in the air whether it would hold up.