On the morning after Donald Trump's first inauguration in January 2017, acting National Park Service director Mike Reynolds was at home preparing breakfast when he received a call from the new president.
Mr Trump, a Republican, was unhappy with photographs published by media outlets suggesting his inauguration crowd in Washington's National Mall was smaller than the one that had gathered for former Democratic president Barack Obama's swearing-in ceremony in 2009, according to two people familiar with details of the call.
Mr Trump ordered Mr Reynolds and the Park Service - which oversees the National Mall - to provide new images from its own photos taken that day to correct the perception that Mr Trump's inaugural crowd was smaller than Mr Obama's. The NPS later forwarded new photos to the White House.
With president-elect Trump's second inauguration a week away and his fixation with attendance numbers at his public events undiminished, crowd size is going to be front and centre again for Mr Trump, media outlets and crowd size experts monitoring the ceremony.
Potential controversy
One person familiar with thinking inside the Park Service said there are concerns that the agency might again be caught in the middle of an inauguration crowd-size controversy, should its images of the number of attendees on the National Mall on January 20th appear unflattering to Mr Trump.
Rachel Reisner, the Trump inaugural committee's communications director, did not address questions about how many people they expected in the National Mall next week.
"The team is putting the finishing touches together for what will be an unforgettable string of events. The Inaugural events will draw supporters, industry leaders, and diplomats of all backgrounds to Washington DC," Ms Reisner said in a statement.
The NPS stopped giving crowd size estimates for events on the Mall in 1996, after facing a lawsuit over its estimate for the Million Man March, a 1995 political protest.
The Park Service will be taking photographs of next Monday's event, although not for crowd size estimates.
Media outlets including Reuters have also received permission to take photos from the top of the 555-foot-high (169 metres) Washington Monument, in the center of the Mall, which will give an overview of the entire inaugural crowd.
A Reuters photo from atop the Washington Monument at Mr Trump's first inauguration was one of the key images that appeared to show fewer people in attendance that day than at Mr Obama's first inauguration.
Crowd size experts estimate the number of people on the National Mall for Mr Obama's first inauguration was between 800,000 and 1 million. Mr Trump drew about a third of that total in 2017, they say. Democratic president Joe Biden's 2021 inauguration was a much smaller event as it took place amid the Covid-19 pandemic.
Crowd size was an ongoing preoccupation for Mr Trump during the 2024 presidential campaign. He repeatedly said his crowds were larger than those of his Democratic opponent, vice president Kamala Harris.
People who attend inaugurations come from all over the country, often in buses organized by political groups that support the incoming president.
'Largest audience to witness an inauguration - period'
G. Keith Still, a renowned crowd scientist and visiting professor at the University of Suffolk in England, analysed Mr Trump's 2017 inaugural crowd in real time, and will be doing so again during next week's ceremony. Mr Still concluded that Mr Trump's 2017 crowd was about one-third the size of Mr Obama's 2009 audience.
Mr Still told Reuters he uses aerial photos to calculate the number of people in attendance, with the help of Google Earth. By calculating the area a crowd is occupying, and the number of people that occupy a square yard, Mr Still says a relatively reliable crowd-size estimate can be made.
He augments his finding by using the number of riders on Washington's metro train system, the size of queues at entry points to the National Mall, the rates at which spaces on the Mall are occupied and car-park occupancy.
"The numbers don't lie," Mr Still said.
The crowd-size controversy consumed the first days of Mr Trump's first term in office.
Sean Spicer
Mr Trump's then-White House press secretary, Sean Spicer, in a press conference the day after Mr Trump was sworn in, told reporters: "This was the largest audience ever to witness an inauguration - period - both in person and around the globe."
Mr Spicer cited figures - that he has since acknowledged were inaccurate but which he believed at the time - that put the number of people in the National Mall at 720,000. Mr Trump, speaking at CIA headquarters the day after his inauguration, said the crowd looked like "a million and a half people".
The NPS issues permits to an incoming president's inaugural committee that allow crowds to gather on the National Mall to watch the swearing-in ceremony.
The permit application drafted by the NPS on behalf of Mr Trump's inaugural committee for next week's ceremony currently contains a placeholder estimate of 500,000 people to be on the National Mall, according to a copy seen by Reuters.
In Mr Trump's 2017 National Mall permit, the same placeholder figure was sent to his inaugural committee. The final permitted figure was 750,000 to 1 million people, according to the NPS permit.
