If you are going by Huaraz on your holiday in Peru,a visit to the arhaeological site at Chavin de Huantar is a must. As for all the excursions in the region, an organised tour, in this case starting with a cup of maté de coca and a stop at the laguna at Queracoha, is the easiest and most economical option. It's also possible to get there via a three day trek from Olleros, which looks really lovely.
Having a fair bit of time to explore the area, I chose to stay in a village nearby for a few days and find a guide whilst I was there. The temple decorations are truly superb, but be aware that you shouldn't expect to find a very large site here. However, it's mainly when you go inside the buildings that the place comes into its own. Here you'll find a maze of corridors and galleries where the acoustics are so truly stunning that they are still much-studied even now.
Many mysteries are still waiting to be unravelled about this civilisation, one of the oldest in South America. But this in no way spoils the visit, which is truly exciting.