President Donald Trump’s inauguration on Jan. 20 in Washington D.C. brought the world’s wealthiest people together to celebrate his return to the presidency, including Elon Musk, Jeff Bezos, and Mark Zuckerberg, who have a combined net worth of nearly $900 billion, according to Forbes. As Trump was inaugurated, longtime Trump supporter Harold Hamm—known for fracking and considered “America’s richest oil man” with over $18.5 billion in wealth running Continental Resources— hosted an exclusive inauguration watch party.