researchers have discovered a series of secret tunnels—passageways once sketched by the Renaissance artist and scientist Leonardo da Vinci and traversed by a widower sick with grief.

An underground tunnel network long rumored thanks to drawings by Leonardo da Vinci under Milan’s Sforza Castle are proven to exist. Ground-penetrating radar and laser scanning revealed that the ...

The Italian polymath Leonardo da Vinci drew his design for an "aerial ... an ornithopter and a hang glider. The pen-and-ink sketch outlines an idea for a flying machine similar to a modern helicopter, ...