The real enemy of museums.
Shows & films might have us thinking that the biggest threat to heritage sites—whether museums, libraries, national parks, churches, or temples—is an elaborate, orchestrated incursion to probe, extract, or deface something of cultural & historical significance for nefarious or heroic purposes. In reality, despite what movies like the Thomas Crown Affair, where a billionaire steals a Monet, Ocean's 12 (complete fiction), where the team steals art, National Treasure, where the Declaration of Independence is stored; & Lupin (Netflix), where a master thief steals jewels & museum artifacts, they are all pure fiction. The Declaration of Independence is indeed housed in the National Archives Building in Washington, D.C., but no one can ever steal it because it is protected by bulletproof glass, inert gas chambers, & surveilled.
The real culprit for valuable artifacts is mold. Even in museums with strict temperature control (e.g., 68-72°F (20-22 °C)), tight humidity control (45-55%), HEPA-filtered air, sealed cases & regular inspections, fungal spores can still infiltrate because spores are microscopic (2-10 micrometers) & ride in on clothing, air currents, or even on new acquisitions. Paper, wood, leather & textiles are essentially fungal food. Of course, molds cannot damage any gemstones but could attack anything organic attached to them. The one exception to the rule is pearls. Why? Because they are organic, made of CaCO₃ (calcium carbonate), aka aragonite & conchiolin (a protein). Mold can grow on them if the humidity is high & damage them.
Real global instances where mold has damaged treasured materials occurred in Denmark, 2024-2026, when they suffered a mold epidemic affecting 12 museums, including the National Museum of Denmark & Skagens Museum. Golden Age paintings, wooden artifacts & ethnographic collections were damaged. HVAC (heating, ventilation, and air conditioning) problems during heat waves (90–100°F/32–38 °C) caused damage to photographs, manuscripts, and textiles in several US and European archives. Even churches & temples in humid climates were affected by molds present as biofilms. All these events happened despite the best practices of the historic & cultural sites.
Mold is the #1 cause of organic material deterioration in museums, which is unfortunately being exacerbated by climate change (heat waves & humidity spikes), & it is capable of destroying objects permanently. They are expensive to remediate. Having said that, even mold cannot compare to the damage done by earthquakes or floods, sea-level rise, or armed conflict. But mold remains the most pervasive, constant & underestimated threat we have today.