Museums, built to house objects from history, science or art, are trying to navigate a host of issues ranging from changes in demographics to demands for transparency and social responsibility. Activists want museums to stop accepting funding from producers of fossil fuels, opioids, munitions and cigarettes, return stolen artifacts to their homelands and create more diverse exhibits and staffs. Museum leaders are under pressure to become more agile and to harness the power of technology, social media and celebrity, while also preserving their traditional roles as guardians of history and educators. This pace of change comes amid new competition from online entertainment and for-profit immersive experience companies, some of which call themselves museums. Smaller museums in particular face funding shortfalls and are starting to sell off pieces in their collections, something that was all but forbidden for decades. Climate change, fires and floods are not only topics of exhibits — they increasingly threaten museum collections and buildings.