The four terrariums are circular stone structures with bowlshaped bottoms and mostly flat surfaces. They are contained in magical spherical fields, which allow matter to pass through, but are designed to shield and contain magical blasts. This keeps the surrounding structures safe in case of an accident. Three of the terrariums are 200 feet in diameter. They contain different biomes and are used for natural research. The fourth is smaller, only 100 feet across, and is located higher up. It houses a security building, as well as a gaol, both overseen by the Perch Guard.