BBC Worldwide have released several classic Doctor Who stories on their You Tube channel, available for viewing to people outside the UK. The episodes are...

The Edge of Destruction (First Doctor, Season 1)
There is an explosion in the TARDIS, rending everyone unconscious. When they come to, Ian and Barbara cannot remember what happened. As they are surrounded by strange events, the crew become suspicious of each other. Is there some alien force manipulating them?

The Krotons (Second Doctor, Season 6)
In a small settlement on an alien world, the smartest students are chosen to become the companions of the Krotons. But when the Doctor, Jamie and Zoe arrive and see one of these students murdered by the alien machine, they are determined to investigate.

Carnival of Monsters (Third Doctor, Season 10)
The Doctor and Jo land on what appears a boat in the middle of the Indian Ocean in the 1920s. But then an ancient marine dinosaur appears, and its seems as though the boat is trapped in a time loop...

The Caves of Androzani (Fifth Doctor, Season 21)
The Doctor and Peri land on Androzani Minor and find themselves in the middle of a vicious conflict over control of a substance called spectrox. When they are exposed to spectrox in it's raw form, they must find a rare cure or die.