The Swedish Vikings of the 8th-10th centuries were a fearsome group, highly skilled at warfare they invaded and settled throughout Northern and Eastern Europe. During the 17th century Sweden again emerged as a great power in Europe with the Swedish Empire gaining territories in Eastern Europe.
Launched in 1954, the first nuclear powered submarine was the USS Nautilus. Nuclear power allowed submarines to operate at high speeds while staying underwater longer than other forms of propulsion such as diesel-electric.
Early submersibles were developed in the 1600s before the first known military submarine was built in 1775. Named the 'Turtle', it held one person and was controlled underwater independently, the first verified submarine capable of doing so.
In 2010 it was estimated that there were over 1 billion vehicles in the world, up from half a billion in 1986. The number of cars on the road continues to increase rapidly year on year especially in developing countries such as India and China.
The Wright Brothers, Orville and Wilbur, were American aviation pioneers who created the first successful airplane, thanks in part to their invention of 3-axis control, enabling the pilot to effectively control the plane.
Zinc carbonates were identified in the oldest known pills which were believed to be used for sore eyes, found aboard a Roman ship that wrecked in 140 BC.
Historically, tin and lead were hard to distinguish between. The Romans called lead 'plumbum nigrum' (black lead) and tin was called 'plumbum candidum' (bright lead).
In the early 1800s when cacti were first taken back to Europe they were cultivated as ornamental plants. Rare species were often sold to collectors for very high prices. Today cacti continue to be grown as houseplants as they are pretty easy to grow and maintain.
Copernicus's skills were not limited to just astronomy. Among other things, Copernicus was also a physician, scholar, economist, translator, mathematician, artist and diplomat.
