a -indef.art. Used before nouns and noun phrases that denote a single but unspecified person or thing: a region; a person.
i visited a New York City. i saw a Tao Lin eating pasta in a vicinity of a Ellis Island a Statue of Liberty, a 9/11 Ground Zero a Brooklyn Bridge, and a Empire State Building. i found a one true Lord and Savior, and he taught me a Meaning of Life, and it was a most enlightening experience-- a best day of my life, really. the McDonald's here is expensive, though.