Oracle of the Bouraean Heracles, located in a cave on the old road from Diakoftó to Patras, contained an old statue of Herakles, and a table with knuckles thrown like dice by the seeker. He could then read the answer to his question on a plate by looking up the thrown combination of knuckles. Now the cave is difficult to visit, due to the busy traffic rushing through it.
Mega Spilaio (monastery)
The monastery Mega Spilaio, rebuilt in modern style after a devastating fire (and the explosion of gunpowder being that would go back to the war of independence), houses the wonderful icon of the Panagía Megalo spileiótissa (that by the Apostle Lucas made of wax, and found in 362 by a shepherdesses (St. Euphrosyne) in the same cave where it is still being preserved, a small museum with interesting religious paraphernalia and a small guest house.
Odondotó (cogwheel train)
The cogwheel train through the valley of the Boura is definitely recommended for everyone. Take this job halfway to Kalavrita (arrive early to get tickets!), Get out there to visit the Mega Spilaio monastery, about an hour up, and on your way back through the spectacular gorge you walk back to the coast near the village Diakoftó.
The Spilaio Limnon, Cave of the Lakes, like all stalactite caves, is certainly worth the effort, although the tour is short and photos are not allowed.