James Martin/CNET

SAN FRANCISCO--Kicking off Uber's fifth anniversary celebration on Wednesday, CEO Travis Kalanick got a bit teary.

"It's unusual for us to take the opportunity to reflect and as I see my mom up here, she's getting a little emotional," he said fighting back the tears himself. "I get this from my mom."

Not known for his soft side, Kalanick took an unusually light and positive tone during a speech he made at the event for employees, drivers, friends and press at Uber's headquarters. During his speech, he talked about the last five years in which Uber has gone from a small startup to the largest ride-hailing company in the world.

"We couldn't have guessed that this is something we would do or something in our future," he said. "But here we are."

Uber, which pairs passengers with drivers via a smartphone app, began operations as a town car service in San Francisco in 2009 under the moniker UberCab. It has since changed its name to Uber and rolled out several different services. Its most popular service is UberX, which lets passengers hail a driver using their own car. Uber is now operating in 300 cities in 58 countries.

The company is also the second-highest valued venture-backed company in the world. It's raised $5.9 billion and has a valuation of $41.2 billion.

The Wednesday celebration was the first press event Uber has ever held at its headquarters. The company converted its all-hands meeting room into a party space, which was decked out with long black curtains and turquoise balloons -- the signature colors of Uber's app. Big screen televisions on the walls displayed slides with promotional images for Uber and company milestones.

During his speech, Kalanick, who donned a dark blazer with a lavender-colored shirt, thanked Uber employees, passengers and drivers. He said that Uber is adding hundreds of thousands of drivers around the world every month. For example, the company has 22,000 drivers in San Francisco alone.

"These are the people who ultimately built Uber from the ground up," he said. "Our driver partners are the heart and soul of this company."

But the road hasn't always been smooth with Uber drivers. Uber was the target of growing driver protests over the past couple of years. In cities, such as New York, San Francisco and Los Angeles, unhappy drivers repeatedly gathered in front of Uber offices to criticize the company for raising fees for its service in some cities and maintaining price cuts in others. Just last month, Uber said it was raising its fees for San Francisco drivers once again.

In his speech, Kalanick also addressed the constant regulatory battles Uber has experienced with lawmakers. Not only has the ride-hailing service faced-off with officials in Germany, France, the Netherlands, India, Thailand, the UK, Spain and China -- to name a few -- it's also been served with lawsuits and cease-and-desist letters in the US.

From Pennsylvania to Texas to Nevada, local lawmakers have spoken out against the ride-sharing service saying there needed to be tighter regulations on things like insurance, car inspections and driver background checks. The state of California is suing Uber, alleging it misleads customers about its business and safety practices.

Kalanick said that even though Uber has dealt with these roadblocks, he thinks the company will ultimately be able to operate legally around the world. He said passengers are asking for the service and drivers appreciate the opportunity to make their own schedules and drive for Uber.

"City after city, we've seen it work," he said. "If we were able to achieve this much in five years, just imagine what we could achieve in the next five years, or the five years after that."