This Children's Special Ticket is a real rarity! The design/layout on the front is slightly different and it's printed in green ink. Plus the 4/D before the serial number is odd too since most of the normal tickets have either the letter "A" or "V" before it. I'll post a photo of the standard Children's Special ticket below for comparison.
I've posted this elsewhere some time ago, but it seems most appropriate on this topic. This is a "Participation Certificate" for the 1926 Sesqui-Centennial Exhibition in Philadelphia. This was essentially a stock certificate for citizens who invested in the fair (this one was unissued). People expected to get some or all of their money back from the fair proceeds, but poor attendance and other factors resulted in a loss, so these effectively became donation souvenirs.