Picnic Island
My guess is that the city of Tampa offered up Picnic Island as a concession to give a large amount of oceanfront land over to industry. They also built a bunch of lifeguard towers, but later realized they would have to pay trained people to sit there. No matter, a lifeguard tower is a great place to watch the sun set.

Off the Beaten Path-Things to do in Tampa Bay Florida « THE TAMPA REAL ESTATE INSIDER-TAMPA, FL said:
[...] Picnic IslandĀ Tampa, Fl Sep 29th, 2008 by RobertĀ [...]
Robert Payne’s Blog » Port Tampa City Library said:
[...] often pass it on my way to Picnic Island, and it draws my eye for the sheer fact that there is not a single structure within miles that even [...]