Consider the following. We humans are social beings. We come into the world as the result of others' actions. We survive here in dependence on others. Whether we like it or not, there is hardly a moment of our lives when we do not benefit from others' activities. For this reason it is hardly surprising that most of our happiness arises in the context of our relationships with others.

Nor is it so remarkable that our greatest joy should come when we are motivated by concern for others. But that is not all. We find that not only do altruistic actions bring about happiness but they also lessen our experience of suffering. Because our every action has a universal dimension, it tells us that genuine happiness consists in those spiritual qualities of love, compassion, patience, tolerance and forgiveness. For it is these which provide both for our happiness and others' happiness. --Ethics for a New Millennium, by His Holiness the 14th Dalai Lama

The source of it all: Plato's Republic

Theory: 

The Mayflower Compact & The Preamble to the Constitution of the United States

William Godwin's Enquiry Concerning Political Justice: Description and Analysis

Marx & Engels: The Communist Manifesto & John Rawls' Theory of Social Justice: Description and Analysis

Jonathan Swift. Gulliver's Travels to the Land of the Houyhnhnms: Description and Analysis

Millenarian & Communal Societies:

Gerrard Wynstanley & The Diggers. Description and Analysis

Mother Ann Lee & the Shakers: Description and Analysis

Amana Colonies: Description and Analysis

Oneida: Description and Analysis

Charles Fourier: Description and Analysis

Robert Owen & New Harmony: Description and Analysis

Etienne Cabet & Icaria: Description and Analysis

Kathleen Kinkeade & Twin Oaks: Description and Analysis and other 20th century attempts at utopia.

Brook Farm 

Hawthorne: Blithedale Romance

Unitarianism

Read about Colonia Dignidad,: a 20th century community in Chile that combined the millenarian societies of the 19th century and the distorted idealism of the Third Reich.

Adolf Hitler: The Third Reich

Overview of the Third Reich. The Platform of the NSDAP is a blueprint  of their goals.

This timeline shows us how they accomplished  those goals.

Eugenics

Burdekin: Swastika Night

------

Painting: Edward Hicks, "The Cornell Farm" (ca. 1848)