In the weeks after Malaysia Airlines Flight 370 vanished, most likely in the Indian Ocean, Australian officials said they knew less about the area they were exploring than is known about the surface of the moon.

It’s actually even worse than that.

Surveys of Mars and Venus are considered around 250 times more accurate than existing maps of the underwater region where Flight 370 searchers are looking—a lightless, virtually lifeless seabed.

There, the contours of the ocean floor have only been approximated by bouncing satellite radar off the surface of the sea, or by taking low-resolution sonar soundings from boats that passed through the area a generation ago. Research indicates the presence of dramatic vistas, including a volcanic plateau and mountains roughly the height of the Swiss Alps. There is so little bacteria that scientists believe a whale carcass would take decades to decompose down there.