The growth of any third political party in the United States faces extremely challenging obstacles, among them restrictive ballot access.

There are more than 100 levels of Collapse-style play to enjoy, all featuring special power-ups and challenging obstacles.

This was a particularly challenging obstacle, one that daunted all but the most athletic Legionnaires.

One of the most challenging obstacles for a beginning meditator is Laziness.

This is a challenging obstacle to overcome as the amount of information required can be severe.

Like other obstacle races, runners navigate through various terrain and physically challenging obstacles.

But for single mothers, transportation and child care are often particularly challenging obstacles to such jobs.

Through her challenging obstacles, she became inspired and lost over 80 lbs.

There's this aspect of running that is probably the most challenging obstacle to just going forever.

Obstacles including residential housing, commercial buildings, fences, a road, and the most challenging obstacle - a large pond.