From the Document: "How often do you think about the things that sustain the American way of life? Safe transportation networks that get us where we need to go. Reliable and secure communications and internet infrastructure that connect us to the online tools and systems we rely on. Clean, available water for drinking and sanitation. Chemicals that are integral to everything from plastics to food preservation to medicines, and the electricity that keeps everything running. What about the malls, sports arenas, office buildings and other commercial facilities that house the places we gather for work and recreation? Even the systems that support our democratic processes--voting machines and the systems that support voting--are critical. Critical infrastructure security and resilience also includes the people who gather for activities that are part of our lives: attending a house of worship, going to a concert or other event, even gathering in a crowded open venue like a holiday market or festival. These are just a few examples of the 16 critical infrastructure sectors and additional subsectors that are absolutely essential to the standard of living that Americans have come to expect and rely on every day. Yet most people take these things for granted. It's not until one of these systems breaks down that we truly appreciate all we have."
DHS Cybersecurity and Infrastructure Security Agency: https://www.cisa.gov/