Paris is hosting a Bastille Day celebration on Tuesday that transcends France's national borders, with troops and warplanes from across Europe participating. This year's grand parade aims to showcase unwavering support for Ukraine and highlight the continent's collective military strength.President Emmanuel Macron, presiding over his last Bastille Day as president, is welcoming around 30 international leaders. The gathering is intended to convey a strong message to both Russian President Vladimir Putin and Donald Trump, affirming Europe's unity and its resolve to defend itself. Among the dignitaries greeted by Mr Macron's wife, Brigitte, was European Commission President Ursula von der Leyen.French President Emmanuel Macron greets senior military officers after his traditional address to the armed forces on the eve of the Bastille Day parade. (AP Photo/Thomas Padilla, Pool)Meanwhile, raging forest fires and a red-alert heat wave are shaking up France’s biggest national holiday, forcing the cancellation of traditional fireworks and firefighters’ balls.Here’s what to know about Bastille Day this year.It commemorates the start of the French RevolutionIt’s celebrated on July 14 because that’s the day Parisians stormed the Bastille fortress and prison in 1789, helping spark the French Revolution that overthrew the monarchy and sent King Louis XVI and his queen Marie-Antoinette to the guillotine.Today, the day is central to the French calendar. Presidents use it to vaunt France’s accomplishments and national pride, mayors host village festivals and families gather for holiday meals.France's Air Force Elite aerobatic flying team "Patrouille de France" (PAF) releases trails of France's national colours as they perform a flyover during the annual Bastille Day military parade on the Champs-Elysees Avenue (AFP/Getty)The centerpiece is the Paris parade beneath the Napoleon-era Arc de Triomphe and along the Champs-Elysees avenue, which inspired Trump to stage his own parade last year.Ukraine is a special guestUkrainian President Volodymyr Zelensky will join Macron along with some 30 other heads of state or government in the special viewing area for the parade.Ukrainian troops will march along the cobblestoned avenue, and Ukrainian co-pilots trained in France will fly two Mirage 2000B fighter jets alongside French air force pilots.Troops from around Europe are marchingOn the ground, the parade will open with around 500 troops from the ″coalition of the willing″ grouping of countries that have pledged to help with Ukraine’s post-war security.Macron said Monday night that it’s a ″great honor″ to welcome to the parade ″all the partners in the coalition of the willing and our Ukrainian friends who will march with us and illustrate its strategic reawakening and our unity.″Ukraine's President Volodymyr Zelensky (R) and his wife Olena Zelensky (L) arrive for a dinner during a "Coalition of the Willing" meeting at Elysee Palace. (Getty)In the skies, aircraft from Germany, the United Kingdom, Croatia, Poland, Denmark, Greece, Sweden, Norway, Spain and Italy will take part.The parade will set a record in terms of number of troops: 6,800 troops will take part in the marching parade this year, compared with 5,810 in 2025.Thousands of soldiers started taking up positions early Tuesday, many taking selfies as helicopters flew overhead.The heat is disrupting the holidayForest fires are raging in the Fontainebleau forest south of Paris and in areas of southern France, as the country suffers through its third heat wave this year.As a result, authorities in some regions — including the French capital — banned fireworks and firefighters' balls customarily held around Bastille Day.The Eiffel Tower's fireworks and drone show was maintained, however, and held Monday night, including a drone formation shaped like the Statue of Liberty — a gift from France to the United States that arrived in New York in 1885 to mark the U.S. centennial, the end of the American Civil War, and friendship between the two countries.