As with any groundbreaking technology, controversy arose, whether it was over a 3-D printed key that can crack open handcuffs or a 3-D printed firearm that could give average Joes on-demand access to guns--no five-day waiting period required.

But even the projects that raised ethical questions or exposed our legal framework to gaping gray areas are, in their own ways, technological triumphs--proof of 3-D printing’s vast potential and popular momentum. Frankly, we can’t wait to see what 2013 has in store for us. Until then, click though the gallery link below for a quick spin through the best and most mind-blowing 3-D printed objects we saw in 2012.