The Model S is a five-door liftback sedan. Deliveries began on June 22, 2012. The first delivery in Europe took place in August 2013. Deliveries in China began in April 2014. First deliveries of the right-hand-drive model destined for the UK, Australia, Hong Kong and Japan came in 2014. As of April 2020, the Model S has two configurations: the Model S Long Range Plus, and the Model S Performance with EPA ranges of 391 miles (629 km), and 348 miles (560 km) respectively. With an estimated 50,931 units sold in 2016, the Model S ranked was the world's best-selling plug-in car for the second year in a row. As of September 2018, the Model S, with global sales of 250,000 units, listed as the world's second best selling plug-in electric car in history after the Nissan Leaf (over 350,000 units).
The Riemann Hypothesis
Today's mathematicians would probably agree that the Riemann Hypothesis is the most significant open problem in all of math. It's one of the seven Millennium Prize Problems, with a million dollar reward for its solution. It has implications deep into various branches of math, but it's also simple enough that we can explain the basic idea right here...