Struggling to craft a strong concluding sentence for my dissertation?

I am a PhD candidate in cultural anthropology writing a 5,000-word dissertation due in three weeks. My advisor insists the final paragraph must leave a memorable impression, but I keep staring at a blank page and procrastinating. I've tried outlining the whole chapter first and free‑writing, yet nothing sticks for that last line. Any strategies to break through this block and finish the essay?