This lifetime field list of geologic sites were intended for geologists, but we see no reason why landscape architects cannot appropriate it as a pedagogical tool. So copy and paste, add a tick box besides each item, and off you go.
No doubt this will take decades to complete, but fear not, Pruned will still be here in the next century and beyond to oversee this challege. Be sure to send journal notes, photographs, hospital injury reports, death certificates, etc.
An erupting volcano.
A glacier, preferably continental.
An active geyser.
The Cretaceous/Tertiary (KT) boundary a.k.a. the Cretaceous-Paleogene (K-Pg) boundary.
A river whose discharge is above bankful stage.
A limestone cave.
An open pit mine.
A subsurface mine. (Bonus point if partly on fire.)
An anorthosite complex.
A slot canyon.
An exfoliation dome.
A layered igneous intrusion.
Coastlines along the leading and trailing edge of a tectonic plate.
A ginkgo tree.
Landscape challenges #1, #2 and #3