Took me a while to figure out what was going on here...
This large group of protesters is making a turn south onto 18th street from M street, after which it's only 5 blocks to the World Bank and International Monetary Fund. The police are out in full-force, as evidenced by a scroll to the south.
The protest only seems to be visible in the West facing Bird's Eye LL imagery. I haven't narrowed down the date yet.