What kind of hole?

     Big Key Pine was one of our quick stops that my group and I visited while traveling from Florida city to the southernmost tip, key west. Big Key Pine is one of the larger sections of the Florida Keys being close to 6,000 acres. This destination, just south of Marathon Florida, is known for two top tourist attractions throughout the Keys. One a wildlife management area called Blue Hole and the other being a friendly animal, the key deer.

 
    Our stop was focused around the blue hole wildlife management park. The interesting fact about the Blue hole that caught my attention was that it was man-made. The park was once a rock quarry that used the limestone to fill the nearby roads and for the construction of the Henry Flagler Railroad. Once the quarry was abandoned, the quarry filled fresh water derived from the frequent rains, and a foundation of saltwater that filters through the limestone bed. With the freshwater having greater buoyancy, it's able to float on top of the denser saltwater.
    Since blue hole contains brackish water, it has a broad spectrum of fish, reptiles, birds, animals that occur on the land and in the waters. During our visit, the naturalist at the location advised us that a couple of saltwater species occur in the quarry due to the storm surge of hurricanes, one being a tarpon. Unfortunately, the tarpon was not seen, nor was the American alligator. What I did see in the waters was a couple turtles and a ton of smaller fish species. Also spotted out of the water was a medium sized green lizard, but no key deer was spotted around the Blue Hole.

    Before we left Big Pine key, we stopped at the visitor’s center in a shopping plaza right before the high way. As we were leaving the plaza, from the corner of my eye I spotted a key deer in which another student and I shouted deer and pointed in the direction of the animal. Therefore the spotting of the key deer checked both of the tourist attractions off our list and we continued our adventure to key west.

 https://en.wikipedia.org/wiki/Blue_Hole_(Big_Pine_Key)

https://www.tripadvisor.com/Attraction_Review-g34085-d142781-Reviews-Blue_Hole-Big_Pine_Key_Florida_Keys_Florida.html