Phineas and Ferb - Season 4 - Eps 29: Steampunx
When Phineas and Ferb discover a commemorative coin from the 1903 Danville World’s Fair, Lawrence recounts the events of the festival to them, in which steam-driven devices were introduced and a set of kids, who were very much like them, were preparing for the highly anticipated event.
About Phineas and Ferb

Title: Phineas and Ferb
First Air Date: 2007-08-17
Last Air Date: 2015-06-12
Status: Returning Series
Rating: 7.873/10 (from 887 votes)
Language: EN
Seasons: 6
Total Episodes: 235
Network: Disney Channel
Genres: Animation, Comedy, Family, Sci-Fi & Fantasy
Production Companies: Disney Television Animation
Synopsis
Each day, two kindhearted suburban stepbrothers on summer vacation embark on some grand new project, which annoys their controlling sister, Candace, who tries to bust them. Meanwhile, their pet platypus plots against evil Dr. Doofenshmirtz.
Cast

Vincent Martella
Phineas Flynn (voice)

David Errigo Jr.
Ferb Fletcher (voice)

Ashley Tisdale
Candace Flynn (voice)

Caroline Rhea
Linda Flynn-Fletcher (voice)

Dee Bradley Baker
Perry the Platypus (voice)

Alyson Stoner
Isabella Garcia-Shapiro (voice)

Dan Povenmire
Heinz Doofenshmirtz (voice)

Jeff 'Swampy' Marsh
Francis Monogram (voice)