CINCINNATI, OH - JUNE 2: Visitors walk past the closed main entrance to the Cincinnati Zoo's Gorilla World exhibit days after a 3-year-old boy fell into the moat and officials were forced to kill Harambe, a 17-year-old Western lowland silverback gorilla June 2, 2016 in Cincinnati, Ohio. The exhibit is still closed as Zoo official work to up grade safety features of the exhibit. (Photo by John Sommers II/Getty Images)

CINCINNATI, OH - JUNE 2: Visitors walk past the closed main entrance to the Cincinnati Zoo's Gorilla World exhibit days after a 3-year-old boy fell into the moat and officials were forced to kill Harambe, a 17-year-old Western lowland silverback gorilla June 2, 2016 in Cincinnati, Ohio. The exhibit is still closed as Zoo official work to up grade safety features of the exhibit.  (Photo by John Sommers II/Getty Images)