Urban density is about how many people live in a city area. It's important for making cities more resilient to climate change. Having a compact city is good, but too much density can be bad for health and happiness. Making cities more compact can help stop urban sprawl. To do this, we need to build up existing areas with mixed-use neighborhoods. Increasing density might be hard because people might not like it. Using numbers to describe urban density can help us understand cities better. But cities are more than just numbers; they have qualities that can't be measured.