The SS United States ocean liner, seen here docked in Philadelphia in 2013, was built in 1952 for United States Lines in an attempt to capture the trans-Atlantic speed record. Landov hide caption

itoggle caption Landov

Rep. Daniel Webster, R-Fla. leaves a House Republican special leadership election meeting on Capitol Hill in Washington on Thursday. House Speaker John Boehner, R-Ohio, is stepping down and retiring from Congress at the end of the month after nearly five years in the role. Andrew Harnik/AP hide caption

itoggle caption Andrew Harnik/AP

Kroto displays a model of his discovery in 1996: a soccer ball-shape carbon molecule that spawned a new field of study and could act as a tiny cage to transport other chemicals. Michael Scates/AP hide caption

itoggle caption Michael Scates/AP

New Orleans Chef Paul Prudhomme prepares barbecue shrimp at the annual White House Congressional Picnic in 2007. Marvin Joseph/Washington Post/Getty Images hide caption

itoggle caption Marvin Joseph/Washington Post/Getty Images

Bull trout are running out of time in Montana as their traditional waters heat up, biologists say. By moving more than 100 fish to higher elevations, fisheries scientists hope to save the species by seeding a new population in waters that will stay cooler longer. Jim Mogen/USFWS hide caption

itoggle caption Jim Mogen/USFWS