Today, there are many hypercars and sedans capable of producing around 200 hp-per-liter, which includes one of the most power-dense car engines ever: the Ferrari 296 GTB's Tipo F163 hybrid V6.

This toxic and extremely volatile element is also the most dense metal in the periodic table, with a 22.59 g / cm³ density. It is a rare element that is extracted from platinum.

Looking at 13 titles over a three months period, Aherne points out that games such as CSR Racing, The Simpson: Tapped Out and Candy Crush Saga rank relatively high in both the free and the top ...