If you're visiting Chicago, explore the city first. After living here for 5 years, we've used most of its great locations for my blog photoshoots.
On top of my list are Honeycomb (also here), Chicago River Walk, The Art Institute of Chicago, Millennium Park, the City Beach, Buckingham Fountain and the Bean, beautiful Chicago bridges, Lincoln Park with its zoo, the farm, and conservatory.
Afterwards it's time to look for hidden gems in the nearby suburbs. Bahai Temple in Wilmette will take your breath away. It is only a 30 minutes car drive from Chicago (they have free parking), and it's totally worth it! The temple is surrounded by fountains and different gardens where you can have a romantic getaway, or a family picnic (I also saw a couple of people doing yoga), not to mention taking great snaps for your Instagram. It's quiet in the morning with very few visitors, later it gets busier. The temple is currently closed, however its usual hours are 6 am to 10 pm.
If you're visiting with kids, there's a playground park nearby (Gillson Park); or, if you like the beach, there's South Beach (make sure to go online and purchase their pass).
We spent a great day there.