On April 6, 2018, Cloudflare launched Argo Tunnel, a service that exposes applications running on local web servers without requiring DNS records or firewall configuration. This makes it possible to use devices like Raspberry Pi as web servers without exposing home networks to the internet. The author demonstrates how to set up and use Argo Tunnel with a Raspberry Pi, including installing Cloudflare's agent, logging in, creating a secure tunnel, serving content from a Rust-based web server, and setting up both the agent and web server to auto-start on boot.