I bought the World jigsaw puzzle (69 pieces) for my 4-year-old grandson. He asked for it after I'd previously given him the U.S. States puzzle. He is thoroughly "into" the world. He knows the names of the countries, where they go. He assembles it, takes it apart, and does it again.
I also bought the GoeCards World for him to use - later! - with his parents. Amazingly, he's super excited about them already. He's obsessed with numbers (populations, etc.) and just soaks up the information. I watched him on FaceTime last night. After he finished the puzzle, he turned to hims mom and said "Let's go play geocards. Now!"
These products are both absolute winners as far as I'm concerned.