Mariana, 23, and Sam, 25, both arrived to their date a little sweaty. Sam, a recent transplant from Savannah, Ga., who rides his bike everywhere in D.C., came to the date on two wheels, while Mariana ...

Just as Earth’s land surface has enormous peaks and valleys, the oceanic world has similarly varied topography. Perhaps the most intriguing of these features is the Mariana Trench — a chasm in the ...