Stone bridges can be made without mortar.
Stone bridges that span many feet and take the weight of all sorts of heavy traffic and cross great chasms, can be made without a lot of things. They can be made without complicating engineering reinforcement requirements and without many totally unnecessary manufactured products, things that unfortunately, in this so called modern age, you might be pressured to using.
But the fact is, they can be made without having any steel or concrete in them. They can be made without nails, fasteners,rebar or plastic holding them together. And can be built without using bobcats or cranes or heavy equipment.
Beautiful footbridges of stone that last hundreds of years can be made without anything, (except a little bit of wood) some rocks and a friendly bunch of enthusiastic people. It mostly needs people doing what they do best - getting along.