On my first trip to Rome my husband and I made a map of all the 'best' gelaterias in the city and then set out to taste each one, doing sightseeing along the way. It was a wonderful and delicious way to see the city. In fact, we liked it so much that we use the same approach in every city we visit. We make sure to take in all the sights AND the best local food of the region...especially the sweets.
Now with a three year old, I think food is an excellent way to begin discussions about different places and cultures. While she sometimes is leery about trying different foods, Lu always likes to hear about (and try!) different sweets from different places. Somehow geography is just a little bit more interesting when she she's trying to locate the origin of a special treat! She loves to talk about what's similar (ingredients, etc.) and what's different from what she's used to.