"A wide sinkhole yawns before you..."
Needle's Bones is a location in Tomb of Annihilation (pg 80). While I've seen many maps for this location, most seemingly disregard the encounter description which includes a 90' wide and 30' deep sinkhole, hundreds of goblin bones littered around the edge and a half submerged, vine, moss and lichen covered skeleton of the Adult Green dragon Ormalagos choked by a sea of lily pads (you will have to add your own frogs though). ;)
Optional separate tree canopy layer to make a "roof" layer (foundry vtt) that allows tokens to shine through.
40x40 : 100px/grid
.jpg + .webp