An experimental plane flying around the world without a single drop of fuel landed in California after a two-and-a-half day flight across the Pacific.

Piloted by Swiss explorer and psychiatrist Bertrand Piccard, Solar Impulse 2 touched down in Mountain View just before midnight (3 a.m. ET).

“I crossed the bridge. I am officially in America,” said pilot Bertrand Piccard, as he guided the Solar Impulse 2 toward its landing after an extended journey around the world.

“Can you imagine crossing the Golden Gate Bridge on a solar-powered plane just like ships did in past centuries? But the plane doesn’t make noise and doesn’t pollute,” Piccard said a live video feed documenting the journey.

The aircraft started its around-the-world journey in March 2015 from Abu Dhabi, the capital of the United Arab Emirates, and made stops in Oman, Myanmar, China and Japan. This is the ninth leg of the circumnavigation.

The trans-Pacific leg of its journey was the riskiest part of the solar plane’s global travels because there were so few places where the plane could make an emergency landing.

Images of the elegant solar aircraft, which has the wingspan of a Boeing 747 but only weighs about as much as an SUV, flying over the Golden Gate Bridge into San Francisco Bay mark a significant achievement.

The plane took off from Hawaii on Thursday, resuming a journey that had stalled on the island of Oahu for almost 10 months.

It lifted off just before sunrise Friday to cheers and applause. On arrival into the skies above California, it flew holding patterns for several hours above San Francisco Bay in celebration of the achievement. Because the plane travels at about the same speed as a car, the Hawaii-California leg took just over 62 hours to complete.

The solar plane looks like a giant high-tech dragonfly and requires near-perfect conditions to fly.

After all, it's the weather -- particularly the sun -- that ultimately decides the schedule of this journey, even with dozens of engineers and experts monitoring the plane's every move.

"Nobody's done this before," managing director Gregory Blatt said. "There's no guidebook. There's no best practice."

The plane’s ideal flight speed is about 28mph, though that can double during the day when the sun’s rays are strongest. The carbon-fibre aircraft weighs about 2.3 tons.

The wings of Solar Impulse 2, which stretch wider than those of a Boeing 747, are equipped with 17,000 solar cells that power the propellers and charge batteries. The plane runs on stored energy at night.