POTUS visits Border Wall
9-17-19
"At the invitation of construction personnel, Pres. Trump pulls out a Sharpie and signs one of the posts of the border wall"
pic.twitter.com/fbDWWfXQrj

See also POTUS explaining tech details of wall:
https://www.youtube.com/watch?v=Te-PDydWAcQ&feature=youtu.be
See also attached vid