Teenager Anthony Peters (29) is doing the 20K.

From left, Melville, Seaman, Burnett and Christie (visible) along with Sanchez and Felipe Dos Santos (hidden) are inbound in a pack of six.

Six pack, now clearly visible, is strung out and now outbound.

Talcott continues with 50K and Elizabeth Flores-Iriarte (105, Mexico) is half way in 5K.

Two laps (2.50km) completed. For leader in 50K, it is 38 laps to go.

Several others stream along, single file, seconds behind.

Fifty-something McGovern (50K) sets pace and teen Jennifer Lopez (34, 20K) tags along for an odd couple of experience and youth.

Lead 50K pack keeps working together early in race.

It's three laps into the race and 37 to go. There's still a long way to go. Current pace would be under 4:00:00. Reachable?

Lead pack is working together on outbound section. Lead two have camera detectable loss of contact, though not to human eye.

Returning the favor, loss of contact in two rear athletes, but not visible to the human eye either. No yellow paddle.

All four are making contact. Judges remain vigilant and rotating positions on course.

Though lapped 40 seconds ago, Jackinsky completes two laps at her own steady pace.