Consisting of eleven obelisks situated along a 1.18 km (0.73 mi) path through the streets of downtown Ithaca, the original Planet Walk leads from the Sun at Center Ithaca to Pluto at the Ithaca Sciencenter. In 2012, the model was expanded 7,630 kilometers (4,740 mi) to include a representation of Alpha Centauri, the Sun's closest neighboring star, at the ʻImiloa Astronomy Center at the University of Hawaii. The addition of the Alpha Centauri Obelisk made it the world's largest exhibition, until the Akaa Solar System Scale Model added Proxima Centauri in 2018 at a distance of 13,370 kilometres (8,310 mi) away from Akaa.