I'm somewhat aware of the fact that there were a large number of explorers, conquerors, and settlers throughout the past few centuries, but I'm curious if it was common for presumably wealthy individuals, groups, or families to travel across continents for leisure.
To what extent did people travel simply for the sake of travel? Were seasonal "vacation" homes common outside of the Roman summer villas I have heard about? Did these folks keep a "home base" in their native country to return to? Were there notable periods when individuals could not even travel safely from country to country?
In the early modern period upper class gentlemen would embark on "Grand Tours." It's not my area of expertise so I can't go into too much detail, but from what I understand such a trip would be seen as a coming of age/rite of passage for young nobles as a way to expose them to European politics and culture, and the destination list would feature many centers of commerce, culture, and government across Europe. It appears to have fallen out of vogue with the advent of industrialism, as travel became less limited to the upper classes, and information about foreign affairs became more reliably accessible from one's country of residence.
Pardon the reference, but there is a wikipedia article on the concept that does soure one of the books I've encountered in the past on the topic.