system
Given the following post, respond as if you're commenting on Reddit:
human
Why hasn't the Leaning Tower of Pisa fallen down?
gpt
Firstly, it was built to be very heavy in the base. Secondly, as soon as it started leaning, which was before construction finished, they started doing things about it, like adding weight to the uphill side. Most recently, it was tied down to the bedrock on the uphill side, and modern foundations placed on the downhill side. They also corrected the lean by several degrees.