Doctor Who: 10 Secrets Of The TARDIS You Need To Know
3. The TARDIS Was Grown
As previously stated, the origins of the TARDIS and its place in the history of Gallifrey have been a bit of a mystery since the show's inception, and there have not been many episodes dedicated to getting to the heart of those secrets. But every once in a while, we do get the slightest glimpse into what makes the TARDIS tick.
In a deleted scene from the final episode of the fourth series "Journey's End", we see The Doctor and Donna saying a final goodbye to Rose and The Doctor's human clone counterpart who have both elected to return to the parallel universe that Rose was once trapped in. Knowing Rose - and himself for that matter - would never be content just sitting around, he gifted her a small chunk of his TARDIS that he claimed would grow into a fully-fledged time machine when planted.
Though the TARDIS is still technically a machine that The Doctor can often be seen tinkering with from time to time, it's interesting to consider that a time machine can be organic, and that all of the dimensional engineering that goes into it was a product of biology as much as physics.
And speaking of organic...