The Onion Router.

Tor is a way to browse in private. It's legal almost everywhere in the world. It's not perfect anonymity but it helps.

Originally developed as a US Navy communications network, it's now regarded by some as "the dark web" (this is slightly misguided), while others call it "sanctuary from violence and oppression". The truth lies somewhere in between. Tor is as nuanced as communication itself and just as valuable or dangerous. It's whatever we want it to be, depending on our motives, although mostly, it's a browser which accesses the hidden Tor network. It certainly provides a vital lifeline for many around the world and it's the closest thing to Internet freedom that we still have left.