Science Journalism students and professionals descend on the iconic science structure in the Sonoran Desert.

Biosphere 2 at sunset on Friday, Oct. 6, 2017. Photo by Kyle Benne / Photo Mentor Science Journalism Fall 2017

The Biosphere 2 was built with 6,500 windows, costing thousands of dollars to clean each time. Photograph by Kacey Seeloff

Left: A hermit crab latches onto a rock at the Biosphere 2 ocean on Friday, Oct. 6, 2017. Photograph by Alyssa Hill

Right: Nicholas Smallwood, a University of Arizona student, is one of the more than 3,000,000 visitors that have visited Biosphere 2 since 1991. Photograph by Ysabella Zammit

Left: In recent years, the 676,000-gallon model of the ocean has fallen into neglect, but selective breeding of acidity-resistant corals might steer the fate of this saline research area for the Biosphere 2 ocean. Photograph by Hannah Hindley

Right: Dragos Zaharescu, a visiting researcher from Georgia Institute of Technology, prepares his samples of ground basalt at the Biosphere 2 as part of an experiment to see how life on early Earth may have formed. Photograph by Marissa Heffernan

Left: Thousands of hermit crabs were introduced into the Biosphere 2 ocean in an effort to kill off the algae. Photograph by Spencer Streips

Middle: Dragos Zaharescu, a visiting researcher from Georgia Institute of Technology, gets a good view of the sunset from above the solar panel slope at Biosphere 2 on Friday, Oct. 6, 2017. Photograph by Nina Kolodij

Right: An unidentified species extends its mouthparts which consist of a sponge-like organ at the end which allows the fly to absorb liquid like a kitchen sponge. Photograph by Naomi Pier

Left: Photographer Kacey Seeloff takes a photo of the Landscape Evolution Observatory research space inside Biosphere 2, on Friday, Oct. 6, 2017. Photograph by Nick Smallwood

Right: The ocean biome utilizes 450 square meters of the 3.14-acre Biosphere 2 structure and includes a coral reef for research. Photograph by Tony Perkins