We admire the men who shaped our country, and rightfully so, the men we see as heroes -- from Alexander Hamilton to Muhammad Ali -- for their confidence and their courage in believing they could change our nation, this idea of self-creation, that there’s nothing holding us back. In them, we see America itself, constantly reinventing itself, fearless, looking out over the horizon at the next frontier.

Then Dido thus, with downcast look sedate: / "Take courage, Trojans, and dismiss your fear. / My kingdom's newness and the stress of Fate / force me to guard far off the frontiers of my state."

The soldiers proceeded to the frontier with caution.

We crossed the frontier yesterday.

The soldiers headed for the frontier with caution.

Everyone has the right to freedom of opinion and expression; this right includes freedom to hold opinions without interference and to seek, receive and impart information and ideas through any media and regardless of frontiers.

Many causes produce war. There are ancient hatreds, turbulent frontiers, the "legacy of old forgotten, far-off things, and battles long ago." There are new-born fanaticisms. Convictions on the part of certain peoples that they have become the unique depositories of ultimate truth and right.

Bernard Kouchner, who established Medecins Sans Frontieres, did not oppose the Iraq war.

Many families went west to make a new life on the frontier.

In the 1880's, this was a harsh frontier town.