Fragrance

Fragrance was a planet once visited by the First Doctor, Ian, Susan and Barbara. It was within the solar system of Alpha Cygni, a sapphire blue sun.

Geography
It was said to have hills of silver and valleys of gold. Like Gallifrey, the trees of Fragrance had leaves of silver. The planet's water was said to be "like wine". Because its ocean was emerald it was probably, therefore, not strictly made of water. Nevertheless, the green liquid, whatever its chemical composition, was apparently vital to the nourishment of flowers, and existed in fountains, as well as the Emerald Sea.

The planet was rich in thorium, one of three elements vital to the safe operation of the Doctor's TARDIS. (AUDIO: The Fragile Yellow Arc of Fragrance)

Sapient life
Fragrance was inhabited by highly-advanced humanoids, whose society had evolved to a near-utopia. The planet's engineers and craftsmen made a device of durable crystal and thorium which would have helped the Doctor better control the TARDIS so as to return Ian and Barbara to their own time. At least some of the residents of Fragrance were of sufficient intelligence to be led into the TARDIS and to comprehend the basics of its operation when guided by the Doctor.

Some of the inhabitants encountered by the TARDIS crew included Rhythm, Rhyme, Iamb, Melody and Harmony. (AUDIO: The Fragile Yellow Arc of Fragrance)