This month's oil impostor: algae ... but up close they should look more like soil or mud. Sometimes, expired animals look suspicious. Last month hundreds of dead sea squirts washed ashore.

The formations look like volcanoes, but a new study published in Nature Geoscience on Monday suggests that they don’t spew lava, but mud. The question of whether the area was formed by molten ...

Below me loomed the Cartagena Mud Volcano – or Volcán de Lodo ... the attendants repositioned our floating bodies, arranging us like competing oil tankers waiting to pass through a canal.