The Fall of the House of Usher
by Edgar Allan Poe
"During the whole of a dull, dark, and soundless day in the autumn of the year, when the clouds hung oppressively low in the heavens, I had been passing alone, on horseback, through a singularly dreary tract of country..."
This story laid the foundation for my love of gothic horror. The way the architecture of the house mirrors the decaying mental state of its inhabitants is a masterclass in atmospheric writing. A must-read.