Fun Tourist Attractions is a curated, visual guide of places to visit
Fun Tourist Attractions calls itself a "visual travel guide," and the name is pretty fitting. It's a large, carefully curated collection of attractions in places all over the world. You won't find stuff that is really "off the beaten path," but it's great for quickly figuring out what some of the most popular attractions are, wherever you're going.
Each location has a list of attractions that are rated "Top," "Good," and "Popular" (with five, four, and three stars). Each attraction has a clear thumbnail and text description, and when you click into it, you get related videos (collected off of YouTube) and blog posts from around the Web.
The information seems to be carefully curated; there doesn't seem to be a lot of noise or spam on the site. I wouldn't use it to plan a whole trip, but if there's a city that you'll just be popping through (say, on a long layover), this site can quickly give you some nice places to visit.