TARDIS

    The TARDIS (aka, Time and Relative Dimension in Space), is a time machine the Doctor uses to travel through time with his companion. A triumph of Time Lord temporal engineering, TARDISes are "dimensionally transcendental" which means that the interior and exterior exist in different dimensions and they can change both their external appearance and internal layout. When the Doctor decided to flee Gallifrey and roam the universe, he stole a TARDIS awaiting servicing for a variety of malfunctions and faults. He has never been able to fully repair it, making his travels often erratic and uncontrolled.

A Good Man?

    Although there is a new face in the TARDIS, the latest version of  the Doctor is still the bravest man in the universe. He uses brain over brawn, proudly defends the Earth, lives life with a passion, and never hides his anger when he sees the suffering of others. The Twelfth Doctor is still the man monsters have nightmares about. Perhaps more tinged by war and sadness than before, this new incarnation is particularly concerned with whether his reputation is as a good man or a bad one.

Photo from: The Doctor Who Site

River Song: Non-Time Lord Regeneration

     It's not just Time Lords that can regenerate. In certain obscure circumstances, such as exposure to energies from the TARDIS, others can absorb Time Lord abilities. The Doctor is delighted to discover that River Song, conceived in the TARDIS, can regenerate just like a Time Lord.

Photo from: WhatCulture.com

Regeneration

    In cases of advanced age, mortal illness, or fatal injury, Time Lords have the ability to regenerate their bodies to create a new physical form. There is a notable shift in personality too, due to chemical changes in the brain. The regeneration process takes many hours. It is hugely traumatic and can cause mental and psychological instability until it is completed.

                                                                                                   

Photo from: TARDIS Wikia