I recently tested out three that work with your iPhone or Android phone: I Am Cardboard's EVA Virtual Reality Viewer (left, $25), the DSCVR Virtual Reality Viewer (above, $30), and Speck's recently released Pocket VR Viewer (below, $70). EVA, DSCVR, and the Pocket VR Viewer are all riffs on Google Cardboard , a novelty cardboard device that Google released in 2014. It lets anyone enter a virtual world for a mere $15.While all three variations that I tried serve their purpose — giving you the chance to experience virtual reality — I liked the $30 DSCVR viewer best. The headset is made of sturdy plastic, with a button in the upper-right corner that's useful for responding to commands on the accompanying Google Cardboard app . To get started using it, all you have to do is scan its QR code with your phone to connect the device with your phone, secure your phone in a slot in the front, and then look through the lens to start exploring Paris (or elsewhere).EVA is also easy to set up. It has a small, sliding controller on the left-hand side, as opposed to a button on top. The one downside here is that the viewer is made of foam. Yes, that made it more comfortable than the other options, but definitely not as sturdy. It kept falling apart in my hands after I placed my phone in front of the lens.