California Academy of Sciences

Stand still for a moment on the Music Concourse and listen. Fog often drifts in from the Pacific here, cool and damp against your face. Under your feet is packed earth and gravel, shaded by pruned plane trees. In front of you sits a long, low building of glass and pale steel. Its roof does not look like a roof at all. It looks like a small green hillside floating above the walls.

This is the California Academy of Sciences. It is an aquarium, a planetarium, a natural history museum, and a working research institution, all under one roof. That combination is rare anywhere in the world. Most cities split these functions across several buildings. Here, you can watch a coral reef, walk through a rainforest, and look up at the stars without stepping back outside. And behind the public galleries, scientists are studying life on Earth.

The Academy is far older than the building suggests. It was founded in 1853, only a few years after the Gold Rush brought a flood of newcomers to San Francisco. That makes it one of the oldest scientific institutions in the American West. Its founders wanted to describe and catalogue the plants, animals and rocks of a region that science barely knew. In those early decades, California was full of species that no one had ever formally named.

The early Academy did not live in this park. Its home stood downtown, near Market Street. Then came the earthquake and fire of 1906. The building was destroyed, and much of the collection was lost. Staff members saved what they could, carrying specimens out by hand as the city burned. Afterwards, the Academy rebuilt here in Golden Gate Park, and its first hall in this location opened in 1916.

Over the following decades, the Academy grew into a cluster of separate halls built in different styles. Then, in 1989, the Loma Prieta earthquake shook the Bay Area once again. The old buildings were damaged. Rather than patch them, the Academy chose to start over. It hired the Italian architect Renzo Piano, the designer behind many celebrated museums. The new building opened to the public in 2008.

Now look up at that roof again — it is one of the first things most visitors notice. It is a living roof, planted with native Californian species chosen to survive the local climate with little extra water. The surface rolls in a series of gentle green mounds. Those mounds are not just decoration. They sit directly above the largest spaces inside, including the planetarium and the rainforest. The roof follows the shape of what lies beneath it.

Here is a detail many people miss. The roof is scattered with round skylights, like portholes. Many of them can open and close. They let in daylight and help warm air escape from the building, which cuts the need for mechanical cooling. The roof also catches rainwater and gives a home to birds and insects. The building was designed to use far less energy than a conventional museum, and it received one of the highest green building ratings in the United States.

Step inside, and the central space feels open and bright. Light falls through the glass ceiling onto the floor of the main piazza. On one side, a great glass sphere rises up several stories. This is the rainforest dome. You climb a spiral path inside it, passing through layers of forest, from the dim floor up to the warm, humid canopy. Butterflies drift past. Small birds move between the leaves. The air is noticeably heavier and wetter than the San Francisco air outside.

At the end of the rainforest walk, you descend into something quite different. An elevator takes you down below the forest floor, into a flooded world. Here, a glass tunnel lets you walk beneath fish swimming overhead, as if you were under the Amazon in flood season. This is part of the Steinhart Aquarium, which has been part of the Academy since the 1920s. Downstairs, a deep tank holds a living Philippine coral reef, one of the deepest exhibits of its kind anywhere.

On the other side of the piazza, a second dome holds the Morrison Planetarium. Inside, the screen wraps above you completely. The shows draw on real scientific data, so the view of the sky and the cosmos is grounded in measurement rather than guesswork. Many visitors lean back in their seats and simply drift. It can be a surprising feeling, sitting under a hillside of grass while the whole universe seems to open above you.

One of the Academy's most loved residents lives in the African Hall. It is a colony of African penguins. These birds come from the coasts of South Africa and Namibia, not from the Antarctic ice. Visitors often gather at the glass to watch them waddle, dive and squabble. The hall around them displays dioramas of African landscapes, which carry over from the older Academy. It is a pleasing link between the old museum and the new one.

And here is the second surprise. The galleries are only the visible part of this institution. Behind closed doors, the Academy holds research collections numbering in the tens of millions of specimens. There are preserved insects, fish, plants, birds and fossils. Academy scientists still lead expeditions around the world, and they continue to describe species that are new to science. The museum you walk through rests on top of an active laboratory.

Before you leave, step back out onto the concourse. Across from you stands the de Young Museum, with its copper skin slowly turning brown. Between the two buildings, fountains splash and the plane trees stand in their neat rows. If the light is right, look at the Academy's roof once more against the sky. That green hill is a reminder of the place's purpose — to study the living world, and, quietly, to make room for it.