Fireworks, flyovers and a 'really long' Trump speech as US celebrates 250th

To play this video you need to enable JavaScript in your browser. This video can not be played Figure caption, 'Could be worse' - Americans on the state of the nation in its 250th year By Bernd Debusmann Jr White House reporter Published 23 minutes ago US President Donald Trump will head to Washington DC's National Mall on Saturday for what he has billed as a "spectacular rally" celebrating America's 250th anniversary. The event, organised by a White House-backed private-public partnership, will include flyovers by hundreds of aircraft and a fireworks display organisers hope will be the biggest of all time. Military flyovers over Washington DC will happen every hour between 13:15 local time (18:15 BST) and sunset, the organisers said, and Trump's new Air Force One will feature in one of the formations over the capital. The president, however, has been accused by opponents of politicising the nation's anniversary event and several music acts dropped out soon after being announced. Extremely hot, humid temperatures of approximately 38C (100F) and a later-than-anticipated start time may also have an impact on the size of the crowd that attends. There is also the potential for evening thunderstorms which could disrupt proceedings. Speaking at an event in North Dakota earlier this week, Trump promised to make a "really long speech" at the Fourth of July festivities "to show that I can do anything". The event, formally known as the Salute to America 250 Celebrations & Fireworks - is slated to begin at 19:00 local time, with Trump expected to speak a few hours later at approximately 21:45e. Other events that were scheduled for earlier on Saturday have been cancelled due to forecast high temperatures . Trump presidency reignites its founding debate - how much power is too much? Published 1 day ago As US marks independence, are the British also celebrating? Published 2 days ago WATCH: 'Beautiful and terrible' - the world reflects on the US at 250 Published 1 day ago The bloody 1770 image that fuelled the American Revolution How the US reinvented the English language The Fourth of July fireworks display is an annual tradition in Washington DC, and Trump has promised that this year's version - which is scheduled to begin after his remarks - would be the "largest fireworks show in history". According to the event's organisers, approximately 850,000 fireworks will be launched from 10 sites across the city, including eight barges on the Potomac River. It is expected to last for 40 minutes - twice as long as the usual display which features about 20,000 fireworks. It is aiming to secure the the Guinness World Record for the largest official fireworks show ever, surpassing the current record set in 2016 by a megachurch in the Philippines. There are concerns, however, that the display could cause dangerous levels of air pollution in the city. Internal National Park Service documents obtained earlier this week by outlets including the Washington Post and Politico