Situated on Chicago's South Side, Promontory Point is a man-made 40-acre peninsula that extends into Lake Michigan and serves as a recreational urban green space for the surrounding community. The distinctive shoreline perimeter, which was constructed in 1938, is comprised of large locally sourced limestone blocks that are stacked and interlocked to form a revetment. The revetment was designed with a gentle slope to stabilize the shoreline, prevent erosion, and dissipate the force of the wave action. In addition, steps and promenades were integrated into the revetment to provide convenient access to the water and promote recreation along the shoreline.

Influenced by its size and location within the Great Lakes, Lake Michigan’s climate contributes to the strong and sustained winds that often generate large and powerful waves that impact the shoreline of Promontory Point. As a result, the limestone revetment has experienced deterioration and erosion that has worsened the structure’s condition over time. There has been a major effort to repair, protect and preserve the historic limestone revetment, as its unique design was a significant component that helped deem Promontory Point an official Chicago Landmark in April 2023 (https://www.promontorypoint.org/).

A major restoration project began in the early 2000’s to address the deteriorating conditions of the limestone revetment at Promontory Point and the greater Burnham Park. The rehabilitation work included demolishing the limestone blocks and installing vertical steel sheet piles and textured concrete. Although this rehabilitation is effective in preserving and protecting the shoreline, it removes the historical, aesthetic, and recreational value of limestone revetment. This image showcases the stark aesthetic contrast between the natural, historic character of the revetment and the new sheet pile and concrete rehabilitation. (Photograph taken by Taylor Zimmerman, McLaren Engineering Group, New Jersey, USA).

Rock Beauty Angelfish on Shark Bend Reef, Pompano Beach, Florida, U.S.A. The rock beauty angelfish (Holacanthus tricolor) is a fish species associated with clear, shallow reef habitats of the tropical western Atlantic Ocean. It can be found from Bermuda to the Bahamas and from Florida down to southeastern Brazil. Their diet consists mainly of sponges, but they have been known to occasionally feed on planktonic animals, small invertebrates, coral, tunicates, algae, and even mucus secreted from other fish. It has a flat, oval black body with trailing black dorsal and anal fins (with yellow and orange margins), a yellow tail, and a yellow face with a black mouth. The juvenile is almost completely yellow, with a black spot on either side that grows slowly to cover most of its body. The lobes of the dorsal, anal, and pectoral fins produce into long filaments as the fish ages. Identification of the rock beauty is based upon the distinctive coloration rather than body morphology. They are most commonly harvested for the aquarium trade, even though their specific diets and territoriality make them a difficult species to keep in captivity.