These exhibits and others that present some highlights of America's faltering progress toward a perfect union go on show for two months in Washington next Tuesday ahead of the semiquincentennial.
The scorching weather that has smashed temperature records across Europe this week shows the growing number and intensity of heatwaves on the continent.
Mosquitoes can learn to associate the smell of the world's most common insect repellent with a tasty meal -- and after training can even prefer to bite people who have been sprayed with it, an experimental study said.