Themassive military paradecommemorating the250th birthday of the U.S. Army, which coincides withPresident Donald Trump's 79th birthday is being staged Saturday in Washington, D.C. The event is expected to include about 6,600 soldiers, 50 helicopters and 60-tonM1 Abrams battle tanks, as well aspossibly 200,000 attendeesand heightened security to match. Opponents of the president's agenda are simultaneouslyrallying in hundreds of citiesnationwide at"No Kings" protestsfollowing days ofnationwide demonstrationsagainst federal immigration raids, including inLos Angeles,where Trumpdeployed the National Guardand U.S. Marines against the wishes of California Gov. Gavin Newsom. Here's the Latest: Here's what to expect at the big parade The tanks are staged and ready to roll.Fencing and barriers are up. Protective metal plating has been laid out on Washington's streets. And more than 6,000 troops are poised to march near the National Mall to honorthe Army's 250th anniversaryon Saturday, which happens to bePresident Donald Trump's 79th birthday. One big unknown: Rain is in the forecast and lightning could cause delays, but the White House said the parade must go one, rain or shine. And Trump said Thursday night that the weather "doesn't matter ... Doesn't affect the tanks at all. Doesn't affect the soldiers. They're used to it." Daylongfestivities celebrating the Armyare planned on the National Mall — featuring NFL players, fitness competitions and displays — culminating in the parade, which isestimated to cost $25 million to $45 million. The Army expects as many as 200,000 people to attend. A special reviewing area is being set up so that the president can watch up close as each formation passes the White House. Cities brace for large crowds at anti-Trump 'No Kings' demonstrations across the US Cities large and small were preparing for major demonstrations Saturday across the U.S. against Trump, as officials urge calm and National Guard troops mobilize. Aflagship "No Kings" march and rallyare planned in Philadelphia, but no events are scheduled to take place in Washington, D.C. The demonstrations come on the heels of protests flaring up around the country over federalimmigration enforcement raidsthat began last week and TrumporderingNational Guard troops and Marines to Los Angeles where protesters blocked a freeway and set cars on fire. Police responded with tear gas, rubber bullets and flash-bang grenades while officials enforced curfews inLos Angelesand Democratic governors called Trump's Guard deployment "an alarming abuse of power" that "shows the Trump administration does not trust local law enforcement." The Army is set to celebrate 250 years with a parade that coincides with Trump's birthday Themassive military paradethatPresident Trumphas long wanted is set to step off from the Lincoln Memorial on Saturday evening, with tanks, bands and thousands of troops. And the biggest question marks are whether it will be overshadowed or delayed by either the weather in Washington or planned protests elsewhere around the country. Falling on Trump's 79th birthday, the parade was added just a few weeks ago to theArmy's long-planned 250th anniversary celebration. It has triggered criticism for its price tag of up to $45 million and the possibility that the lumbering tanks could tear up city streets. The Army has takena variety of stepsto protect the streets, including laying metal plates down along the route. The daylong display of America's Army comes as Trump has shown his willingness to use his fighting forces in ways other U.S. presidents have typically avoided, inviting anarray of lawsuitsand accusations that he is politicizing the military.