What a new bridge over Baltimore's Patapsco River will look like is still very much a matter of speculation. But one design stands out.

A momentary loss of propulsion or electricity aboard the massive cargo vessel as it maneuvered in a tight channel in Baltimore may have triggered a cascade of events leading to the bridge collision.

Theories abound about who is responsible for the attack and how they did it. On Wednesday, Russia arrested eight men alleged to have set off a truck bomb. Ukraine says Russia planned the attack.

In the Indian state of Meghalaya, one of the wettest places on Earth, villagers are separated by rivers and valleys. To stay connected, they coax tree roots to grow together into living bridges.