The UK videotape release was on two cassettes, each consisting of three episodes edited to run together and also adding some previously unseen material.

The compilation episodes consist of previously unseen material.

The design was meant to be limestone - a material hitherto unseen on the block - with a concave, curved front.

The second volume even contained 'previously unseen material', a few minutes that were cut to make the programmes fit their time-slot.

Nice article and full of interesting references of unseen material.

A special show featuring unseen material and favourite bits from the series so far.

One study centers on determining the composition of "dark matter" - the mysterious, largely unseen material that astronomers think makes up most of the universe.

Indeed, computer simulations show that galaxies remain stable only if they are surrounded by spherical halos of considerable unseen material.

The actual Olympics, geared to families with children over 5, will consist of challenges like identifying unseen materials by their touch or smell.

The extended episodes have a total of more than 40 minutes of unseen material.