KanjiJLPT N2
Trace

tracks, mark, print, impression

Mnemonic

icarus plummets from the sky after his wax wings melt. His leg drives deep into the sandy shore on impact, leaving a perfect imprint. Centuries later, that fossilized leg-shaped crater is the only trace anyone can find of the boy who flew too close to the sun.
Additional thoughts
Picture a single dramatic footprint fossil in coastal rock — Icarus's final landing spot. Trace = the remnant left behind. Leg hitting earth + Icarus's fall = evidence of what once was.
Quick recall
icarus falls and his leg stamps into the earth, leaving the only trace of his existence.

Details

The keyword for 跡 is trace. This kanji refers to the marks, footprints, or remnants left behind after someone or something has passed through or existed in a place. It conveys the idea of a trace, track, or vestige — evidence of what once was. It can also extend to mean ruins or the remains of historical sites, carrying a sense of following or detecting what has gone before.
On'yomi
せき
Kun'yomi
あと