The history of aviation is packed full of amazing aircraft, used both commercially and in military operations. How much do you know about these magnificent flying machines?

A Stock Symbol - or Ticker - is a series of characters (usually letters) that represent the company on a stock exchange. Most are simple abbreviations of the company name but some are more creative than that. Test your knowledge of some of the best ticker symbols with these multiple choice questions...

Various scales and charts have been developed to measure everything from the pungency of peppers to the intensity of earthquakes. Test your knowledge of some of them with these multiple choice questions...

The vastness of space is mind-boggling for most of us, yet we remain fascinated with life beyond our own planet. Test your knowledge of our solar system with these multiple choice questions.