Remnants of (great) adventues

[Elvensilver]

In a world full of dragons and evil liches your party is just the latest generation in a long line of great heroes and villains. But how can you depict that? How can you include some small details to make the world more rounded, give it a sense of depth and past, and show the immensities of foes and dangers that could still be around?
So I made this thread to gather some ideas, or some recollections. Where did you hide the parts of the destroyed artifacts, did you just leave the body of the defeated dragon to rot, and did you return to the grave of the poor sod killed at level 4 to build a memorial?
Please give any ideas, details, etc. pertaining remnants of adventures!

[Eldan]

I've had a player who played a librarian (Archivist in 3.5), and took this very seriously. Investigated everything at the library first before going on an adventure. Since after a while, he got access to some very grand, old libraries, including a planar one at higher levels, I started preparing sources for him to find. Often, old legends, sometimes the diaries of adventurers that had been in the same places, or attempted the same things. Often dusty, half-crumbled (so that they wouldn't know about all the details), never opened in a century.

Was nice. They used it to tactical advantages quite a few times, since they knew that 150 years ago, Grimnir the Bold or whoever had encountered a special tribe of goblins on that pass, or there was a certain kind of monster in those caves that had a very special weakness.

[Krowmeat]

I think the only world-marking thing my current party has done was co-ordinate the abandonment of a hamlet built on a series of floating crystal islands that were kept afloat by blood sacrifice in a whirlpool hidden in the caldera below the town. Not sure what happened there - While the crystals were being kept afloat by the sacrifice, the water level of the whirlpool would rise the longer it went without it, too. Could be that was nothing and that place is just a ruin of skewed houses resting atop some nifty boulders, but I like to think that the water level of that whirlpool just kept rising, and that the buildings are floating on top of that now.

[Xapi]

My current campaign's main focus is about finding out what happened exactly when the last great hero party killed a Dragon 30 years ago, but let another dragon go (this second dragon conquered a Dwarven mountain Stronghold right after that, and the official story is that she was hidden and the adventurers never saw her).

They will meet the five surviving members of that party, with the fifth one turning out to be the BBEGal.