What and why is the only city outside of the current United States visited by George Washington? What lasting effect did his journey have on him?

Washington visited Bridgetown Barbados when he was 19 years old to accompany his half-brother who was suffering from tuberculosis. The hope was that the warmer climate would help ease his brother's symptoms. Sadly, his brother did not improve with the warmer climate and died shortly afterward. Since George looked up to his big brother, his passing would have been a big blow for the young Washington.

The trip had several important impacts on his life. For one, he was amazed by the British troops that he saw there and their system. It is said that this experience encouraged him to be active in the military. Washington also contracted Smallpox while there and his developed immunity had an important impact on his strong support for inoculations for his troops.

https://smithsonianassociates.org/ticketing/tickets/gw-in-barbados
https://www.mountvernon.org/library/digitalhistory/digital-encyclopedia/article/lawrence-washington/