Based on information provided to the Equine Injury Database, horses suffered fatal breakdowns at a rate of 1.3 per 1, 000 on synthetic tracks, 1.6 per 1, 000 on grass courses, and more than 2 per 1, 000 on dirt.

FORBES: Making Racing Safer For Horses, Starting With The Surface

It will be a one-lane dirt road, closed for seven months of the year by snowfalls on the 2, 900-metre (9, 500-foot) pass south of Shatili.

ECONOMIST: On the Chechen road, to Georgia

Highway Mega Trail ( etgeocaching.com): This tour includes 2, 000 caches, hidden every 528 feet, along approximately 200 miles of paved and dirt roads in southern Nevada.

WSJ: Aliens, Dinosaurs and Colonial History: Geotours Across North America Draw the Cache-Mad