After a day filled with tension and fissures in the powerful NATO military alliance, President Donald Trump and First Lady Melania Trump gabbed with their counterparts at a cocktail party with a jazz band. The pair arrived at a cocktail party with fellow world leaders and spouses at Cinquantenaire, a park designed in the 19th century. The first lady wore a $7,450 Elie Saab white patterned dress, changing out of a navy blue dress by Belgian designer Raf Simmons for Calvin Klein.