"The Great Cloudwall" is [CloudFlare](https://www.cloudflare.com/), the world's largest MITM proxy([reverse proxy](https://en.wikipedia.org/wiki/Reverse_proxy)).
It is called this in reference to the [Great Firewall of China](https://www.comparitech.com/privacy-security-tools/blockedinchina/) which does a comparable job of filtering out *some* people from seeing web content(ie everyone in mainland china and some people outside) while at the same time those not affected to see a dratically different web, a web free of censorship of such images as ["tank man"](https://en.wikipedia.org/wiki/Tank_Man).
Cloudflare similarly prevents those in southeast asia and elsewhere who have poor internet connectivity from accessing the websites behind it(for example, they could be behind 7+ layers of NAT) unless they solve multiple image CAPTCHAs. Cloudflare also has a massive [harassment problem](https://web.archive.org/web/20171024040313/http://www.businessinsider.com/cloudflare-ceo-suggests-people-who-report-online-abuse-use-fake-names-2017-5). [Tor users](https://www.torproject.org/) and [VPN users](https://airvpn.org/topic/23090-cloudflare-often-bans-my-ip-address/) are a victim.
