Commercial satellite imagery shows that a small building surrounded by a high wall has apparently been newly constructed built in Pyongyang's Kim Il Sung Square.
Martyn Williams writes at 38north.org:
High-resolution imagery from Friday, December 18, shows the building is at the western end of the square, right across the street from the viewing platform used by Kim Jong Un and party officials during parades. A second building is located adjacent to it but outside of the walled-in area.
Medium-resolution imagery indicates that construction on these buildings began sometime between December 8 and 12. The purpose of the buildings is unclear, although they could be related to the upcoming Eighth Party Congress that is expected to take place in January.
Earlier in December, Daily NK reported that North Korean authorities planned military and civilian parades to mark the event, which would almost certainly take place in Kim Il Sung Square.
More at 38North.org.