For fun, I have been researching my ancestory, using a mixture of wikitree.com, ancestry.com, and findagrave.com. One answer to this question may be that these are bad sources and I shouldn't trust them.
According to wikitree, my ancestor was born in Virginia in 1690, went to Trabzon, Turkey at some point, got married in Trabzon in 1711, had a kid there, and then went back to the US to die in North Carolina in 1764.
Why would he have done this? What was going on in Trabzon at the time?
EDIT: I should have said English ancestor. Obviously the US had not been formed.
Most probably he was engaged in trade, as Trabzon was historically an important port city. The most well known English overseas ventures are those in North America, and the East India Company, but there were also various trading companies formed around the same time (c. 1600) to trade with places like Muscovy, North Africa and Turkey. One possibility is that he was working for the Levant Company, which was chartered in 1581 to trade with the Ottoman empire and Levant and had a monopoly on this trade until the mid 18th century. However most sources seem to indicate that English traders only traded from Mediterranean ports at this time, so the choice of Trabzon specifically is a bit strange.
Did your ancestor have an English last name? Or was it Turkish? Or Pontian?