The building with 3 domes in the foreground on a hill top. The city in the background is Los Angeles.
That's Griffith Observatory!
It's an astronomical observatory, planetarium and museum in the midst of Griffith Park. The land plus the money for the observatory came from Griffith J. Griffith.
Besides the telescopes, planetarium and exhibits, there's a cafe, shop, and theatre and often great views of the Hollywood sign and the Los Angeles basin.
It's been used as a filming location for several films including Rebel without a Cause and La La Land.
Admission is free, but parking can be problematic. I recommend you check out their page on "Getting Here."
As others have said, it's the Griffith Observatory. It is situated in Griffith Park, which is home to many other attractions.
One can reach the observatory via shuttle, driving your own car (though parking is very minimal), or hiking up one of several hiking trails in the park.
The larger center dome houses the observatory's planetarium, which has several shows, all narrated IN PERSON by a live narrator! Not a recording!
The dome on your right houses a solar telescope, called the Triple Beam Coelostat, which feeds three instruments in the exhibit halls below, where you can safely observe the sun and some of its phenomena. Here's an example (video): https://youtu.be/6UZFjjWIOd8 (Warning: NEVER look at the sun without proper safe instruments and filters, like those used at the observatory.)
The dome on your left houses the Griffith Observatory's Zeiss Refracting Telescope, which opens (almost) nightly (weather permitting) to look at the moon, various planets, and sometimes far more distant celestial objects. A video about it: https://youtu.be/VjzmaiPLr4g
Best of all admission to everything, except the planetarium show, is free in perpetuity, compliments of "The Colonel" Griffith J. Griffith.