Cold connections are the opposite of soldering - no heat! Wirework is one example of cold connections: for instance, wrapped loops, and all-wire bundles. You can also punch holes in metal and use rivets or tacks to create a join without using heat. (Patti's #4 project, Mixed Metal Collage, uses tack rivets to create a beautiful 3D fall-inspired pendant!)
Riveted Mixed Metal Collage Pendant by Patti Bullard, from her 4th DVD in the Metalworking 101 Beginner Series.