Click on the red marker for locations of the History Trail markers. Some locations have more than one plackard.
If you can not see the map on a iphone then you need to disable "Prevent Cross-Site Tracking,
Safari on iOS strictly limits embedded third-party cookies by default, which can block Google Maps from rendering.
1. 0pen the iPhone Settings app.
2. Scroll down and tap Safari.
3. Under the Privacy & Security section, toggle off Prevent Cross-Site Tracking.
4. Refresh your browser page to see if the map loads.