Groppo is a tiny hamlet between Manarola and Volastra. You will drive by if you arrive by car on the coastal road (parking is free), or you can take the small bus from Manarola. For the best experience, hike here from Manarola or Volastra.
There are only a few colourful houses here, so you can quickly discover the village. It's really quiet, so come up here if you feel you have met too many tourists at the seaside railway stations.
The Cinque Terre Wine Cooperative can be found in Groppo as well; that's where most of the Cinque Terre wine is made. Stop by in their shop (by the road); it's full of delicious local products and souvenirs.
Just below the village you can also find an old olive mill, but it's closed at the moment.