Several of these have sprung up in my garden and I have no idea what they are or where they came from.
They are in full sun, have reached about 3.5-4 ft tall, and just started blooming this weekend! The stalk/trunk is quite thick and the leaves very feathery and delicate looking.

Any help in solving this mystery would be appreciated.

Maybe Cosmos? Cosmos

I think cosmos also.

You guys are amazing. Thanks so much!