The site is Hillman Wonders, nothing flashy, but nicely laid out with a list of what this travel writer considers the world's must see sites. There are some very obvious choices, from top to bottom of the top 100 list, like the Pyramids in Egypt. Or the Eiffel Tower. Some you're likely to know. New York's skyline. The very top of the page is why it's important, scroll down for a few words on how to best see it, and often a few other notes about what you're looking at.
Those are the obvious. How about something obscure, you'll probably never see? Other than on line. The Meenaskshi Temple in India. Amazing architecture, especially since it's 700 years old!
For something much more modern, check out this luxury hotel in the Arabian Gulf. It looks like a sail caught on a stiff breeze. There's a neat comparison to show you just how tall it is, compared to the Empire State Building.
If you don't do too well on his top 100, you can check out the top 1,000places to see around the world. Much longer list, but no pictures or details.