Medieval PVP Arena is an survival, mini game map made for minecraft.
In real life back then we have Colosseum, In current time we have Stadium, but in Minecraft we have Medieval PVP Arena.
Since this is a PVP map it means it supports minecraft online multiplayer sessions. I assume you can fit as much people as you want because this map is initially a server map by 88_MPH.
It was created as a survival map on the server.
88_MPH is kind enough to share this map for free for anyone to download.