Guess the Event Where this Pic was Taken and Win a Copy of John Riley's Book

Guess where the photo was taken to win a FREE BOOK (History of Greenfield Park). We'll give them a hint this time. It was taken in the Park on Churchill near Hollingdrake's Store during the summer and it was taken at an event that most youngsters 10-15 years old really looked forward to each year.

What was the event?
JohnR.