Design a Web System for Selling Concert Tickets Worldwide

Design a worldwide concert ticket selling system that presents authenticated users with 10 available seats at a time, ensures no two users are shown the same seats simultaneously, prevents previously shown seats from reappearing in subsequent batches, and enforces a 2-minute window for seat selection or browsing. Requests to purchase seats outside this window or seats the user was never shown must be rejected. The system must be resilient against malicious actors disrupting the seat presentation process and operate globally with 99.999% availability.