Diwali, the Festival of Lights, is celebrated by millions of people around the world, making this a fitting month to turn our attention to the engineering and technology of light.
From illuminating our homes to carrying information across continents, generating electricity and allowing us to see the otherwise invisible, engineers have found some extraordinary uses for light.
So, for this month's Question of the Month, we want to know: which invention involving light has changed the world the most?
There's plenty of room for debate here. The LED transformed lighting and displays, lasers underpin technologies ranging from manufacturing to communications, fibre optics carry enormous amounts of the world's data, while solar cells turn light itself into useful electrical energy.
And perhaps we've missed the invention you'd put above all of them.
Tell us what you picked and why in the comments. We're particularly interested in hearing from engineers who've worked with these technologies firsthand.
