10 Most Iconic Alien Planets In Modern Doctor Who
9. Darillium
After being mentioned on several adventures as an important place in the Doctor and River Song's future, Darillium finally appeared in 2015's The Husbands of River Song as the location of their final date.
Darillium was famous throughout the universe for its Singing Towers - two monolithic rock stacks which seemed to 'sing' thanks to wind passing through its underground cave systems. The planet was also the crash site for the Harmony and Redemption - a space cruise liner for criminals brought down by a meteor strike.
It was following this crash that the Twelfth Doctor and River Song spent time together under the many moons and burnt skies.
Using the Halassi Androvar Diamond recovered from the crash, the Doctor invested in building a restaurant in front of the towers to take River Song to. With a balcony view and the Towers' song in the air, the Doctor finally kept his promise that they'd spend one final night in each other's company.
Using the TARDIS to jump forward in time, the Doctor ensured that the restaurant was constructed, and they had a table, for his final meeting with her.
This would be the last time they'd see each other before she would go on to die in the Library in 2008's Forest of the Dead. It was there in the Library she planted the story of the Singing Towers in the head of the Doctor's earlier incarnation - meaning he knew about their fated night on the planet from the start.
What the Doctor failed to mention to River, however, was that their final night on Darillium would actually last twenty-four years due to the planet's rotation.
Intergalactic Travel Advice: Book well in advance.