Most participants in a human "marble"run

According to Official Guinness Records,

The most participants in a human “marble” run is 510, achieved by Johnson & Johnson Middle East (UAE), in Dubai, United Arab Emirates, on 1 March 2017. The record attempt was done as a team building exercise.

For a complete list of 2017 records, please visit 2017 Guinness Records in United Arab Emirates.

Other United Arab Emirates records that might interest you:

• Largest whiteboard
• Most people performing push ups
• Largest flower arrangement / structure
• Most mechanical energy produced by pedalling on static bicycles in one hour
• Largest glow in the dark painting
• Most chest to ground push up burpees in one hour (female)
• Fastest mobile bed