Waymarks that can be placed in this category should be large and interesting roadside attractions you have come across in traveling around the world, across the country, or even in your hometown.
A website listing an excellent collection of roadside attractions for Canada is Large Canadian Roadside Attractions, the list is very large and building all the time.
Also there is an excellent web site for roadside attractions in the U.S. Roadside America.
Here's a few other roadside related websites that may be of additional assistance.
List of World's Largest Roadside Attractions;
Atlas Obscura;
Legends of America;
79 Weird Roadside Attractions Road Trip;
RoadTrip America;
Roadsidepeek;
22 of the World’s Most Bizarre Tourist Attractions
Please note that tourist sites such as Trip Advisor or general tourist information sites (which commonly include attractions, food, lodging and history of the area) are NOT for unusual Roadside Attractions in various country's and are thus NOT allowed. Perhaps your discoveries should go in Official Local Tourism Attractions.
We'll be adding more as they're found. In fact, if you know of any other roadside attractions related website not already listed here, let us know, we'll be glad to add it to our list. Thanks, & enjoy!