Engineers plan to descend the north leg of the Gateway Arch Thursday, weather permitting, to take samples of stains on the exterior of the monument. The excursion will be one of the few times since the Arch was completed in 1965 that anyone has climbed (with permission) on the Arch's exterior.
Mitch Ryals Engineers removed windows and opened the hatch at the top of the Arch Tuesday to prepare for "industrial rope access" to take stain samples.
A crew of engineers began installing an anemometer (which measures wind gusts) and the system of ropes Tuesday that will anchor two individuals as they descend the Arch's north leg. The ropes will exit through the hatch at the apex of the 630-foot-tall Arch and loop through each of the windows along the north side.