Dungeons, complete with Iron Maidens, racks and iron bars, seem to be standard features of medieval castles, for example, the Tower of London.

Executions also were held at the Tower of London in years past.

Famous people like Anne Boleyn or Sir Thomas More are commemorated by plaques in the gardens on the adjacent Tower Hill.

Gargoyles (the animated 1990s series) included an episode with a London memorial to the Battle of Britain.

Have you ever seen the movie of the Battle of Britain?

Is that something I should see?

Juveniles, such as I, myself, once was, were encouraged to view Battle of Britain, The Dam Busters and other World War II movies to understand history.

Knowledge of history is said to be important, lest we repeat the mistakes of the past.

Little is known, however, about some periods of history.

Much less is known about the life in Earth's oceans.

No man has been able to go to the deepest depths of the ocean in order to study life down there.

Organisms in the ocean are crucial to explaining why this planet's atmosphere is so rich in oxygen.

Plankton are a crucial part of that oxygen-making process and also an important food source for sea life.

Quite frankly, while the ocean is fascinating, I prefer to study it from a safe distance.

Rough seas make oceans fearsome transport barriers and many have died when ships sank.