The Quinta Vergara Amphitheatre sits at the upper end of the park, a tiered open-air bowl in a natural fold of the hills. It was built specifically for the song festival and remains its permanent stage, although it now also hosts pop and rock concerts throughout the summer.
If you are in Chile during late February, this is the place to be. The festival itself runs nightly for a week; tickets are notoriously hard to get for the headline nights but easier earlier in the week. Outside festival time the amphitheatre is open to walk through and gives a good sense of the scale of the event.