If you love Batman and want to instill that love in your own children I recommend osmosis. Get the symbology recognized while they are young and you will have a little nerdling forever. It worked for me and my daughter with Sailor Moon and it will work with you and your kids with Batman. You just need to find the right ways to do it. And part of that solution could very well be decor. Also books. They make a ton of introduction books for Batman. Anyway I was browsing Etsy when I found this really awesome shelf that you could use in a nursery or kids room and thought I would share.
The shelf is made by Maria_Tsarinnik and it is small but mighty. It can hold lego figures or something more purposeful like a baby monitor which you could aim down at your little ones crib. You can check out the listing for Batman by clicking the link here.
They also make some other cool shelves for superheroes such as this Captain America one.
PurplePollen on Etsy has a bunch of really cute shelves including Star Wars but those deserve a whole new article. Seriously check out their shop which you can do by clicking the link here.
