The National Portrait Gallery in London closes temporarily for one day after an “unexpected” issue affecting the venue’s operations. Multiple reports say the closure is linked to a power outage, which disrupts access to the gallery. The gallery is currently hosting the “Marilyn Monroe: A Portrait” exhibition, and the temporary shutdown prevents visitors from viewing the display during the closure period. The outlet reports describe the problem as unexpected and do not attribute it to any specific cause. The gallery’s closing is presented as a short-term measure while the issue is addressed, with the public-facing impact limited to the day in question. Details about the duration, restart timing, or whether visitors are offered alternative arrangements are not specified in the provided accounts. No reports included here mention injuries or damage, and the focus remains on the temporary closure of the attraction due to the outage.