Ancient Nemea is a compact site, well two sites really as it is split into two. The main site houses a museum, the remains of the Temple of Zeus, bathhouse, Christian basilica and some graves. The second part, just around the corner is the Stadium. In its heyday it was as important as Olympia for athletic festivals. Athletes used to prepare for competition at the main site before heading to the stadium to compete.
Entry into the stadium is through the same tunnel used by the athletes over 2000 years ago. There is even some ancient Roman graffiti visible in the tunnel.