I always go straight to the domain registry and whois URL's:
https://www.whois.com/...hallenge-daytona.com

There you go. Registered by Triple Performance, the company that runs Challenge Almere-Amsterdam by the looks of it.
I'd say Daytona is a pretty good bet based on this.


Don't know anything about Daytona, but given all the shark comments on this thread, couldn't you do a swim in Lake Lloyd at the speedway? Just googled and found some triathletes did an open water swim event there...