Since ancient Greece, researchers have tried to isolate special rational points on curves. Now they have the first ever formula that applies uniformly to all curves ...

Christina Majaski writes and edits finance, credit cards, and travel content. She has 14+ years of experience with print and digital publications. Robert Kelly is managing director of XTS Energy LLC, ...

Since Philadelphia is arranged on a grid system, the mostly one-way roads are easy to navigate. Helpful maps are posted along street corners across the city – watch for the "Walk! Philadelphia" signs ...

Find historical weather by searching for a city, zip code, or airport code. Include a date for which you would like to see weather history. You can select a range of dates in the results on the next ...