Large etchings of numbers signaling opposition to Trump appear on National Mall (washingtonpost.com)

I'm impressed at how precise the construction of each numeral is for something that must have been done by hand, covertly, without much equipment- probably at night. By my estimate each numeral is at least 100' wide and 140' tall.

Another source: https://www.yahoo.com/news/us/articles/mystery-8647-etched-d...