Summer ain't over until Sydney Sweeney says so! The 28-year-old took to Instagram on Sunday to share some sizzling hot pics and vids from a recent birthday "trip to mars" ... AKA, one of the US' beautiful lakes possibly in Arizona or Utah by the looks of the rocky red formations surrounding it. One of her favorite things to do! In the carousel, the Anyone But You star poses in a variety of different revealing swimsuits, including a black one piece featuring a plunging neckline, a white one piece, and a sparkly gold bikini...