Unless you're planning to buy used equipment, most interchangeable cameras come with a kit lens which is a good choice for most kinds of photography.
So the kit lens will typically be a zoom with wide enough angles for landscape and architecture photography and enough telephoto focal length to catch some up close portraits.
That might be a good starting point and then later on, look at getting longer telephoto if you want to photograph sports or wildlife or wider angle if you find the kit zoom lens wasn't wide enough.
Primes will be lighter and faster (wider aperture) to photograph interiors, such as cathedral interiors.
One feature for travel photography which seems to be dropping off is GPS or geotagging. For awhile, manufacturers were putting in GPS in their cameras but in the latest models they've removed them.
For instance, Nikon put it in their midrange DSLR the D5300 a couple of years ago but I think they removed it in the D5500 which replaces the D5300. But you might still be able to find good deals on the D5300.
Once you geotag, a program like Adobe Lightroom will display the location where the photo was taken on a map, provided that the camera or the GPS device locked into enough satellites when the picture was taken. When you take thousands and thousands of pictures over years of travel, you may not always remember where the picture was taken, unless you're putting keywords on each pic you take and retain in your library. So geotagging or embedding the GPS coordinates of where the picture was taken could be useful for identifying some of the pictures years on.
Of course, if you take pictures with a smart phone and have a data connection, it's geotagging those pictures. But for dedicated cameras, you have to look for certain models or get peripherals to get the same GPS data.