A rare ceremony is scheduled for the Washington Monument, which is currently closed to visitors.
On Thursday, the National Park Service will accept a plaque from the people of Ireland that will be hung in the staircase of the monument. It highlights the connection between the 2016 centennials of the park service and Ireland's Easter Rising.
The stairwell of the monument has scores of commemorative stones, most of which were received in the mid-19th century. The park service says new donations are accepted "only in very rare circumstances."
The monument is closed until 2019 for a modernization of its elevator, which experienced a series of breakdowns after the monument was damaged in a 2011 earthquake.