...Atlantic City, NJ.
The country's first boardwalk was built at the popular vacation spot in 1870 as a way to help keep sand out of hotels along the beach. (Although in my experience, nothing can keep sand from getting into anything and everything that comes near it.)
Today, the Atlantic City boardwalk stretches for nearly 4.5 miles.
And so Carmen upholds her reputation for being a "supergeekknowitall." :) Congratulations!
If you want to know more about the history of the boardwalk in Atlantic City, look here or here.
I wasn't surprised by the Coney Island guesses though... I've never been there, but to me, it seems more legendary that Atlantic City and so an obvious guess.
I love these old photos. I can't believe how close the water comes to the boardwalk! Cooool:)