Map tile serving system
Design a map-tile serving system for a global maps product handling 500k tile requests/second at peak. Tiles are needed at ~20 zoom levels; the world at high zoom is billions of tiles, but only a tiny fraction are ever requested and request patterns are extremely skewed toward populated areas. The underlying map data updates periodically (new roads, businesses) and those updates must propagate. Describe the tile addressing scheme, the static-vs-dynamic split, caching/CDN strategy, and how you handle invalidation when the map changes without re-rendering the whole planet.
Clarify scale and constraints first. Propose a clean component breakdown, then go deep on the hard parts (data model, bottlenecks, consistency, failure modes) and name the trade-offs you are making.