Approximately how long ago did humans begin working with bronze?

The Bronze Age marks a really important period in human history, a time when people started using metal to make tools and weapons on a large scale. Before bronze, people mainly used stone, hence the Stone Age. But stone tools are quite limited, right? Bronze is much stronger and easier to shape. Bronze is an alloy, a mixture of copper and tin, and it allowed for much more sophisticated designs. Now, the Bronze Age didn't start at the same time everywhere in the world, but in Britain, it's generally accepted to have begun around 2,000 BC. If we're thinking in terms of "ago," that puts it roughly 4,000 years ago. While metalworking existed earlier in other parts of the world, the widespread use of bronze in Britain really took off around this time, transforming society and technology. So, while other answers might seem plausible, 4,000 years ago is the most accurate estimate for the start of the Bronze Age in Britain.