I'm collecting stories about weird ownership interests people encounter in Alabama foreclosure or tax sale investing. For example, I've recently fielded questions about tax sales of improvements only, and life estate only.

FYI, sometimes local government entities will lease their land to others, who build improvements that benefit themselves and the local government. Examples include airport authorities who lease land to others for hangers and distribution centers.  The Port of Mobile leases land to a wide variety of businesses. The land is owned by a tax exempt entity, but the improvements are assessed and taxed to the tenant.  Other times, private individuals sign long term ground leases to companies.  If you have a very valuable corner of land, and refuse to sell it, McDonalds might sign a long term lease and build their building. At the end of the lease, you will own the land and the improvements.  In that case, the dirt and the leasehold improvements are assessed separately, and each one pays taxes.

Life estates usually come into being when a parent engages in DIY estate planning and deeds the family home to the children, while retaining the right to use the property for the rest of the parents' lives. The parents have a life estate and the kids have a remainder interest.  In that case, only the life estate is assessed for taxes. If it is sold for unpaid taxes, one has only a life estate, which lasts until the parents die, and then disappears.  It doesn't have to be a parent/child situation, that is just the most common example.

What kind of weird ownership interests have you encountered?