BOSTON — Happy birthday to the Boston Marathon, which turns 120 today.

Here is something to know about this year’s running of the planet’s most venerable footrace:

Nation’s oldest marathon

The Boston Marathon was born on April 19, 1897, when a handful of men fueled by steak and whiskey conquered a course initially laid out over 24.5 miles. In 1924, the route was extended to the classic 26.2-mile marathon distance to conform to the Olympic standard. Since then, it’s become the premiere marathon in the world, this year drawing 30,000 runners from 99 countries — the third-largest field in the history of the race — and 1 million cowbell-clanging onlookers.