The still active cone of Mount Batur is a relatively young and small volcano located in a middle of the huge crater of its grander ancestor: diameter around 14km.
This scenic trek takes you through the Gunung Agung area, through coffee plantations, rice fields ands rivers. The trip typically covers about 15 km in 3 hours.
Hop on a 4 wheel drive ATV for a tour through Bali's natural environment. Perhaps not the lowest impact way to explore the island, but good fun nonetheless.