Hmmm, for the first time in months I took down the box of terrain that I thought worth taking with me when I moved, and found much of it damaged, mostly by very bad packing on my part. (I was rather depressed when packing to move, and as a result not nearly as careful as I should have been.)
Rather than whine about the loss, entirely my fault this time around, I am going to ask what deaths have other people's terrain pieces suffered?
Best is when a piece becomes just plain worn out - it has been loved to death and will live on in warm memory.
I have had a castle eaten by mice. (This one I think is funny, the original Castle Works was easy enough to build that I can replace it pretty quickly if I want.)
Two pieces that have been sat upon.
One that was lightly trodden upon. (Not actually killed, just maimed.)
One that was carried off by a ferret, never to be seen again. (We watched it being carried off, a Village Works fishing hut.) Ferrets are energetic, but not very subtle, thieves.
One or possibly two that have been stolen. (I cannot find the Tower Bridge, I remember packing it, but cannot find it. I don't think that it has been stolen, but...)
A bunch of Arena Works that popped apart during damp weather (as a result I find myself using Elmer's more often than UHU these days).
A bunch that have been given away over the years, which may or may not be dead (at least one survives that I know of, though it is showing signs of wear - the Skaven Caves/ Pirate's Cove build).
A bunch that have been used to death (my original Village Works terrain comes to mind). Torn, faded, dampened by spills, but loved. Much is still being used despite the damage.
And a bunch thrown out while moving, as too fragile or not up to snuff.
Others?
The Auld Grump
(This was actually a concious decision on my part, I have gotten too attached to prizes in the past.) I may build another mill one of these days, it came out rather well for all its speed.
. My first Matboard building (the keep from CastleWorks: Classic), as well as several prepared pieces, about four buildings worth (already glued to Matboard), suffered major damage. Some of my pictures including the keep show the damage, mostly visible on the roof, which steadily worsened over time. The balcony filled with water, and the ink damage was the first noticeable, followed by severe warping, and a sudden give to all the glue joints. Since then, the only real damage has been from my cats, who have a bad habit of sitting on hard, raised surfaces after coming in from the rain, and have done it to both my Maiden water tiles, and my CWU paperlinx tiles 
.