The photographs feature fish that have been specially treated to make the stained skeletal tissues visible through the skin and flesh. The technique, developed by Dr. Adam Summers, uses dyes, hydrogen peroxide, a digestive enzyme and glycerin to make the flesh seem to disappear. Photo: This image of the butterfly ray (Gymnura crebripunctata) helped scientists study the joints in its wings. (Photo by Adam Summers)

A woman wears a flower crown during a Summer Solstice celebration on June 21, 2021 in Krakow, Poland. The summer solstice represents the longest day of the year, with the most hours of sunlight, and is celebrated by various cultures worldwide. (Photo by Omar Marques/Getty Images)

General view of the Jacquemus Menswear Spring Summer 2020 show on June 24, 2019 in Valensole, France. (Photo by WWD/Rex Features/Shutterstock)

Paris Fashion Week, Spring/Summer 2014 Haute Couture collection by Charlie Le Mindu. (Photo by Yoan Valat/EPA)

A woman in yukata, casual summer kimono, poses for a photo at Fushimi Inari Taisha in Kyoto, Japan on October 2, 2019. (Photo by Matthew Childs/Reuters)

People play on a beach along the Arabian Sea on a hot summer day in Mumbai, India, April 29, 2016. (Photo by Danish Siddiqui/Reuters)

A man pours water on his camel on a hot summer day in Ahmedabad, India, May 18, 2017. (Photo by Amit Dave/Reuters)

A mahout bathes his elephant in the river Sabarmati on a hot summer day in Ahmedabad, India May 21, 2017. (Photo by Amit Dave/Reuters)