Cloudflare outage Post Mortem and Monocle

Recently I read quite interesting DNS outage post-mortem from Cloudflare:

It’s really fascinating to read about BGP security and at the same time quite concerning that some Tier-1 ISP still doesn’t have proper BGP security in place.

When I read technical details of the post-mortem - I also found out about Monocle tool that allow to investigate BGP routing (issues):
Btw, Monocle is written in Rust :)