5. “The Ballad of the Green Berets” by Staff Sgt. Barry Sadler
An unlikely pop hit to be sure, this song was #1 on the Hot 100 for the entire month of March 1966 and hit the #2 spot on the country charts at the same time. Wikipedia tells me it was written, in part, to honor the first Native Hawaiian killed in the US war in Vietnam, a young man named James Gabriel Jr. The recorded version dropped the direct reference to Gabriel. While the song makes no direct mention of the Vietnam War either, the message was clear as US involvement in the war began escalating. Troop levels more than doubled from 1965 to 1966, from about 184,000 to more than 385,000.
4. “California Dreamin’” by the Mamas & the Papas
I’m surprised to learn this classic only made it to #5 on the Hot 100. Along with the above, it might be the definitive song of the year. Celebrated as a harbinger of the emerging counterculture and a slice of an equally emergent California sound, it was the first hit for the group and a signature song of the era. (It was produced by Lou Adler, who’s half-Mexican and half-Jewish and raised in Boyle Heights.)
3. “Uptight (Everything’s Alright)” by Stevie Wonder
This song was #1 on the R&B charts for five weeks from January to February, the same time it peaked at #3 on the Hot 100. By March it was on its way down, sliding from #2 to #7 on the R&B charts. The young Stevie Wonder shared writing credits on the song, his first hit with a writing credit and a sign of greater things to come. Stevie’s voice change is prominent here, another sign of things to come for the future father of nine kids.
2. “19th Nervous Breakdown” by the Rolling Stones
Nancy Sinatra and her boots kept this out of the top spot on the UK charts while the Green Berets did the same in the US. Peaking at #2 in March, this Rolling Stones classic has that signature sound of the early group. I love the mix of the “British sound” with US blues in this era of the band. They were well on their way to legendary greatness.
1. “Nowhere Man” by the Beatles
Talk about on their way to greatness. This song is from the Rubber Soul album, the first album people started to realize this was more than your average pop band. The lyrics of “Nowhere Man” help it stand out. John is experimenting in life and in art, and he’s written a song that is not about boys and girls in love. What is it about? It’s deep, sometimes confusing, and filled with antiestablishment possibility. But who knows?
LATINO LIKE ME 
You never know how a song will affect you over the years. “California Dreaming” was a part of my life since it first came out, and was associated with the band that recorded it. Still is, but the video I see in my mind when I hear it now is from Chungking Express.
I know what you mean. I don’t have the direct reference for the song in 1966 but in my mind it’s a cinematic song, something that plays in movies (or on TV) to give a certain feel. I grew up with it because of that frequent use.