After 20 years of construction, Switzerland just completed the world's longest and deepest rail tunnel. The 35-mile Gotthard Base Tunnel runs 1.5 miles under the mountains connecting northern and southern Europe. In other transportation news, Paris just banned all cars made before 1997 in a bid to reduce air pollution. Tesla's battery Gigafactory is set to host its grand opening on July 29th, while a new report claims that Volkswagen is spending $15.5 billion to build a gigantic battery factory of its own. Consumer Reports ranked the Toyota Prius as the car with the best gas mileage it has ever tested, and Ford announced that the Fusion Energi can travel further than any other plug-in hybrid on the market.Chile's central grid has quadrupled its solar capacity since 2013, and now the nation is generating so much solar energy that it's giving it away for free. Meanwhile, the world's newest sovereign nation is taking shape between Croatia and Serbia, and it could be powered entirely by algae. In other energy news, China added half of all new wind power installed in 2015, and the world's largest commercial rooftop solar array was installed atop a shopping mall in the Philippines.
3D printing technology started small, but now it's being used to print entire houses. This week Chicago-based architecture firm WATG unveiled plans for the world's first freeform 3D-printed house. In the Netherlands, a team of designers has developed a sturdy modular home made from 24 layers of cardboard that can be assembled in a single day. And we explored why round houses are able to withstand hurricanes that destroy traditional homes. Finally, in wearable tech news, MIT researchers developed a way to 3D print programmable "fur" that could be used in textured surfaces, and London's Science Museum hosted a space-inspired fashion show.