In this page, I will post everything related to background information in the Pikmin series (rests from the human civilization, for example). I will try to classify them (decorations, machines, and so...)
Made by humans
A bell. It is similar to the Danger Chime in Pikmin 2.
A glove which resembles the Five-man Napsack.
A tyre. Tyres appear in Pikmin 3 and are found in the following areas : Stagnant Sea, Sandpit Kingdom.
A gutter in The Rustyard. In Pikmin 2, it's possible to find gutters as well (in the Shower Room, for example)