Happy 54th Birthday to BiscayneNPS! 🎂🥳 #OnThisDay in 1968, President Lyndon B. Johnson signed Public Law 90-606 to create Biscayne National Monument! #FunFact: 95% of the park's nearly 173,000 acres are underwater. 🌊 #BiscayneNationalPark #NationalParkService #HappyBirthday #Florida #Anniversary