[maxerickson]

The US has 3dep, which is a USGS program to aggregate and publish various federal and state data.

Not really the same thing you are talking about, and not global, but it can be fascinating to look at. You can see old logging railroads and things like that in Michigan, and trace them to where they collected and dumped into rivers.

[heliodor]

Catalog map is at:

https://apps.nationalmap.gov/lidar-explorer/

Click on a covered area, click one of the green icons listed next to each data set, then click on Potree Viewer in order to get to the 3D viewer (Potree in this case; I haven't tried the other one much).

Scroll down the sidebar and change the dropdown that says "intensity" to say "elevation". Right below that, tweak the slider bar to select the min and max elevations so that the landscape you're looking at gets colored with all the colors. At the very top, reduce the radius to 0 and increase the strength to 1.0. And if your hardware can handle it, increase the point budget to whatever is still responsive. Lastly, under filters, deselect everything except ground, if you want to see the ground instead of vegetation and buildings.

Also worth mentioning is the shaded relief derived from all this data, which you can find at:

https://apps.nationalmap.gov/3depdem/

It's very detailed and is a great starting point for your exploration of an area before jumping into the 3D viewer.

[colomon]

Ooo, I'll have to look into that. I had a fun couple of days a few years ago comparing Google Maps satellite images from St Clair County, MI with the old maps which showed where the Interurban ran. It was really impressive how much you could still see the routes from above, even though the tracks were torn up 80+ years ago...

[maxerickson]

The resolution can vary a lot. Michigan tends to have a lot of very nice data because NOAA has recently been doing scans of the Great Lake shorelines.