30 greatest NFL rivalries of all-time

Here is a look at the 30 greatest rivalries throughout NFL history.

Countless factors go into what makes a great rivalry.

Historical context is crucial.

Sometimes a rivalry can lose its spark due to extensive winning and losing streaks, or simply a lack of games against each other as of late. But with history to lean on, a rivalry can stand the test of time.

Parity is also a major factor.

A rivalry may not feature an abundance of all-time great games, or a signature moment to define it. In certain cases, though, a series record that is close to an even split can resemble a rivalry that will always leave pundits split on predictions.

But perhaps the most common source of a rivalry is a constant battle for a division title. Some divisions feature such intense competition in this area, that essentially any game between its members carries the aura of a heated rivalry, regardless of current standing. It is a feeling that has been birthed through years of building hatred for a familiar opponent.

And, of course, animosity among fans is a significant contributing factor as well.

Other rivalries do not involve teams themselves. Instead, they involve a pair of players or coaches that have been linked forever by history, trash talk or both. This can occur through constant head-to-head showdowns, statistical comparisons or a combination of the two.

On rare occasions, a player even develops rivalries with his own teammates, typically creating an unfortunate situation for everyone involved.

Regardless of the circumstance, rivalries are something that makes sports special, and professional football is no different.

Here is a look at the 30 greatest rivalries in NFL history.

Next: 30. Baltimore Ravens - New England Patriots