Well, in the 1840s the British railroads adopted a flag, lamp and semaphore signal system where red meant danger, white meant safety and green indicated proceed with caution. They took their ...

The earliest warning signals were in the form of green and red lanterns, installed in London as far back as 1868, primarily to guide horse-drawn carriages. As the 19th century unfolded ...

The blue light, a dot compared to the full orb of a traffic signal’s green, yellow and red, is for traffic law enforcement. When that blue dot shines, it means the signal is red. It helps law ...

So you may already have intuited that a green flag on the beach signals that everything’s OK, while a red flag indicates dangerous conditions. But what exactly are those conditions—and how ...

Many Black people celebrate Juneteenth with a flag that is red, black and green. Some social media users called out a Virginia city for merging July 4th and Juneteenth holidays and only using red ...