From Modest Displays to Mega-Oceans: the Race to Build the Largest Tanks
Public aquariums trace their origins to the Fish House at the London Zoo in 1853, which relied on small slate-and-glass tanks linked to gravity-fed reservoirs. Early municipal installations faced tight physical limitations. Plate glass could not withstand the hydrostatic pressure generated by water depths exceeding five or six feet. As water depth increases, hydrostatic pressure scales at approximately 0.433 pounds per square inch per foot of depth. Early curators were trapped between shallow viewing depths and murky, stagnant basins.
For more than a century, civil engineers attempted to scale up displays using concrete bunkers fitted with tiny, reinforced viewing portholes. This compartmentalized approach gave visitors the sensation of looking into maritime laundry machines. The visual threshold broke open during the late 1960s with the introduction of industrial polymethyl methacrylate (acrylic). Unlike silica glass, acrylic can be cast into thick, structurally resilient blocks, molecularly bonded on-site, and polished to near-total optical transparency.
When the Monterey Bay Aquarium unveiled its 1.2-million-gallon Open Sea exhibit in the 1990s, it demonstrated that pelagic predators could survive in a purpose-built enclosure without crashing into walls. That milestone triggered an international wave of construction. Major cities realized that massive marine habitats served as powerful anchor attractions for urban tourism and real estate developments.
