I would definitely recommend the Riverwalk in downtown Pueblo. It's thirty-two acres, with walking trails, historical information, gift shops, and cute little restaurants and coffee shops lining the trails. There are several stops along the walking paths, such as the Center for American Values, which offers tourists information about the history and people of Pueblo.
They also renovated this area recently, adding a memorial to Pueblo's veterans. There's a bridge that stretches over the water, and a large stone engraved with all the veterans' names. You can even look up a name on a computer and find out if that person is listed on the memorial. They also added a memorial to the two towers, which is simple but quite beautiful.
The Union Depot is also a great stop for some history. They have a museum, as well as a restaurant and gift shop. The Depot is available for catering and for wedding ceremonies, but my favorite part of this place is just wandering the property and looking at all the old trains and vintage cars that are part of the historic exhibits.
If you're visiting Pueblo in the autumn (September - October), I'd definitely recommend Pueblo's ghost walk as well. A tour guide takes visitors through all of Pueblo's haunted hot spots. It makes for a great family field trip, or just an interesting and informative night out.
If you're visiting Pueblo