This is the 3929th most frequent Polish word.
sopot
Sopot: A seaside resort city in northern Poland, located on the Baltic coast.
In this sentence, 'Sopot' is used as a proper noun referring to a specific geographical location.
Sopot to piękne nadmorskie miasto w Polsce.
Sopot is a beautiful seaside city in Poland.
Here, 'Sopot' again denotes the name of the city, used as an object of the verb 'chose'.
Planowaliśmy wakacje nad morzem, więc wybraliśmy Sopot.
We planned a vacation by the sea, so we chose Sopot.
In this sentence, 'w Sopocie' is the locative case of 'Sopot' used to indicate location.