Larry Niven's Ringworld and its sequels is a classic case of science fiction world building on an enormous scale.
The Ringworld of Niven's novels is a hoop around its star, the construct of a dying race, desperate to create not only living space, but energy interceptors.
Ringworld details the first expedition to the Ringworld, and what they discover there.
He is approached by Nessus, a 'Piersons Puppeteer' who asks him to lead the exploration of the Ringworld.
The Puppeteers, one of the most technologically advanced species in Known Space, discovers the Ringworld through a deep probe.