The nonviolence practiced by men like Gandhi and King may not have been practical or possible in every circumstance, but the love that they preached -- their faith in human progress -- must always be the North Star that guides us on our journey.

CNN: Obama: 'Peace requires responsibility'

But while EU leaders love harmonisation in theory, in practice progress has been very sticky.

ECONOMIST: Huddled masses: stay out | The

It was a schism that led to the formation of the establishment-approved Women's Tennis Association in 1973 -- which will be marked this year by the WTA's "40 Love" commemorative campaign, a celebration of four decades of progress in the women's game.

CNN: How women cracked tennis' glass ceiling