Chicago (Transit Authority)

I really feel like this band should be under these archives. Definitely not  "Post-Crisis Chicago," but their first couple of albums are considered by many to be very good works of progressive rock. It's really hard to think of them as regular rock music.

Chicago Transit  Authority (their debut album and a double album) featured a minute-long track that consisted of people chanting "The whole world is watching" which leads into the incredible song  "Someday (August 29, 1968)." A majority of these songs are more than 6 minutes in length and "Liberation," the longest track, is 14:38. Also, the quaint "Free-Form Guitar" cannot go unmentioned. Although it is not an incredibly enjoyable song to listen to, we have to give it credit for being extremely avant-garde and unconventional. Overall this album is very instrumentally driven and has a sound unlike typical rock groups of the time (or those from any other time). Perhaps one of the biggest distinguishing factors is their unique variety of instruments, particularly the heavy use of brass and wind insturments (indeed this becomes the staple for Chicago during their entire career).

Chicago II (another double album) is no less progressive than its predecessor and it shows off a more-developed form of jazz fusion. Although "25 or 6 to 4" was an instant mainstream top-40 hit, it is clearly a step above its other 1970 hit counterparts. "Ballet for a Girl in Buchannon," "Memories of Love," and "It Better End Soon," however are what set this album apart. Each of these are songs with multiple movements and are all around 10 minutes in length. Chicago II has a distinct sound that cannot be found in any other band. It features a developed form of jazz fusion combined with brass instruments.

With Chicago III (yet another double album), the band is moving towards a more mainstream sound, but the 22-minute 6-movement "Travel Suite" as well as the 5-minute 5-movement "An Hour in the Shower" and the 15-minute 6-movement "Elegy" keep the progressive rock tradition. However, it is less jazz-powered than the previous albums. After Chicago IV, a live album, Chicago's music becomes much less progressive and it soon reaches the point that Chicago fans refer to as "Crisis." Post-crisis Chicago is a sad pop-based band and could in no way be considered progressive.

If you have never heard anything by Chicago here are some sample videos:
Introduction (from Chicago Tranist Authority) Sorry for the poor quality
http://www.youtube.com/watch?v=YOroWOamrpQ
Ha ha Free-Form Guitar
http://www.youtube.com/watch?v=P_tJ3CtFlU4
25 or 6 to 4
http://www.youtube.com/watch?v=aSOaoPDO16Y

That might not be the best selection of Chicago music, but it's what I could find.

Last I heard, if you want to help get them included, the band bio is in desperate need of a knowledgeable writer. Someone else can confirm, but people who are serious about having them included and also know things about the band and their history can get them here much faster.

Does the song Oh, Thank You Great Spirit from Chicago VIII count as prog?