More than just a source of warmth and light, fire enabled all the modern technology, built the community, and activated our imagination.
To produce anything we use today, we need high temperatures: a subway, a computer, an AI. Arguably, there can be no intelligent civilization without fire. Hard to disagree when our current definition of intelligence is a metal box mimicking human capabilities.
Aside from practical application, fire also built communities. It brought us together, allowing us to share stories, values, and knowledge. Which in return, spurred language which fostered collaboration.