Erebor
In "The Desolation of Smaug", the hobbit Bilbo Baggins, and thirteen dwarves, while traveling to Lonely Mountain, pass through the black forest of Mirkwood, where they are attacked and captured by giant spiders. The spiders are then attacked by the Wood Elves, led by Legolas and Tauriel. Tauriel in particular saves Kíli by killing two spiders that attacked him, but the Elves subsequently take the dwarves as prisoners for trespassing on their land.