In Unicast routing, one IP maps to one physical server. In Anycast routing, a single IP address (e.g., 8.8.8.8) is announced via BGP from dozens of physical data centers globally.
When a client requests 8.8.8.8, Internet routers forward the packet to the topologically closest data center announcing that IP. This inherently solves global latency by ensuring the TCP Handshake is terminated at the edge, rather than traversing the ocean.