League of Legends' most popular arena, Summoner's Rift, was updated yesterday across the Team Builder and various bots gametypes, bringing — among other changes — a complete visual overhaul to the map. You can check out a side-by-side comparison of the old and new Summoner's Rift map above; a lot of the updates, particularly to the map's NPC monsters, are fairly striking.
For more on Riot's philosophy for renovating Summoner's Rift, read the dev blog's announcement of the changes from this past June.