A collective is a group of people who are organized around an issue or to accomplish a goal together. Collectives can have many different features, but one that unites them is an egalitarian or non-hierarchical way of relating. Meetings are often conducted using the consensus process.
A collective household, also called commune or intentional community, is a group of people living together in a house, apartment, or in some other arrangement such as sharing land together. Collective households may be organized around a specific project such as a business, around raising children, or based upon shared interests.
Or you may use a coincollection to help you visualize the history of your state or country.
Collecting State Coins - With 50 states to collect from, you may want to start collecting state coins just from your home state and then branch out to neighboring states rather than tackle the whole of the US at once.
Collecting Roman Coins - The Roman Empire spread over a large area, so Roman coins are a surprisingly cheap way to start your coincollection as well as being a unique piece of history.