Peter Jackson's LOTR Films Database
The Fellowship of the Ring
Summary of events
[The Fellowship go down the stairway, then enter a bigger chamber.]
Gandalf: Yet me risk a little more light.
[Gandalf's staff lights up, illuminating a massive pillared hall.]
Gandalf: Behold! The great realm and Dwarf-city of Dwarrowdelf.
The Two Towers
Summary of events
[The Hornburg and Deeping wall can be seen in Helm's Deep.]
The Return Of the King
Summary of events
[Gothmog motions to an orc archer. The archer aims and shoots his bow at an Gondorian sentinel, hitting him in the breastplate, fatally wounding him, and knocking his body off the tower he's standing on.]
Commentary
The Dwarfs may have enlarged existing caves to carve out the city, but it's still an insanely impressive feat. Note that the pillars appear to be solid, one-piece stone—so they were probably carved out, meaning that the Dwarves did basically all of it.
Commentary
In the books, the ancestors of the Gondorians built the Hornburg long before Rohan was a thing. It's a massive and impressive fortress.
Commentary
What's that armor made of? Tinfoil? In real life, any high-quality steel breastplate is mostly immune to arrow attacks, though it can be dented a bit.