Salesforce is celebrating the capping of the tallest building west of Chicago, and the views are astounding

Salesforce CEO Marc Benioff and San Francisco officials are marking the laying of the final beam — a construction milestone known as "topping off" — at its new global headquarters in downtown San Francisco.

"They take the last structural beam and everybody signs it," Elizabeth Pinkham, Salesforce executive vice president of global real estate, said in advance of Thursday's planned ceremony. "Then they hoist it up to the top."

The building rises 1,070 feet high and is the tallest U.S. office building west of Chicago. Salesforce, a cloud-computing company that specializes in customer relationship management, is the "anchor tenant" and will occupy floors three to 30 and the top two levels, 60 and 61. Rather than designating the two top floors for executive offices, Salesforce will keep them open to all employees and their guests, Pinkham said.

Other tenants will include Salesforce partner Accenture, which wanted proximity to the enterprise tech company, CBRE and Bain & Company. Construction is set to be completed in July. The landlords are Boston Properties, which has a 95 percent stake in the building and Hines, which owns the rest.

Right now, the building still looks like a construction site — there is no trace yet of the fancy office furniture synonymous with tech company offices — and construction workers are in the process of building out the skeleton of the building and installing the windows.

"I'm used to being up there with no windows, so it's going to be weird with windows," said Pinkham.

Click ahead for a first look.

— By CNBC's Harriet Taylor
Published 6 April 2017

Salesforce is the largest tech employer in San Francisco, with more than 6,000 local employees. The company has its name on all kinds of buildings downtown.

We visited this week and took a ride to the top. The elevator feels wobbly, but none of the construction workers seem concerned.

Salesforce's Pinkham takes us on a tour around the 60th floor, which still has few windows, although there is a guard rail.

These giant windows offer unobstructed 360-degree views.

Here's the view south toward Silicon Valley.

The Bay Bridge from 60 floors up.

We tower over everything else in downtown San Francisco.

At 1,070 feet, Salesforce Tower even dwarfs the iconic pyramid-shaped Transamerica Tower, which is 853 feet high.

There's one point in the city that's higher still: The top of the Sutro TV tower, located on top of a peak in the middle of town. The structure is 977 feet high, shorter than the Salesforce Tower, but it's sitting on a peak that's 834 feet above sea level.

Here's how the windows look once they're installed.

Heading back down, we saw these construction workers hard at work on the 5th floor.

Workers are also building the park next to Salesforce Tower. Employees will be able to cross over to the park from the 5th floor.

These trees, the first greenery to arrive, are waiting to be planted.