A scuba diver exploring the underwater coral reef, surrounded by a blue hazy environment.

Tom Metcalfe

Tom Metcalfe is a freelance journalist based in London who writes mainly about science, archaeology, history, the earth, the oceans and space.

Latest from this author

Mali - Bamako - Mixing purple dye

Knowledge of how to make the bright purple dye was a valuable trade secret to the Phoenicians.