Uber, the cab service, which has been in the eye of several storms celebrated its fifth birthday on June 3.

In the last five years, Uber has seen several ups and downs - including being embroiled in legal tangles with regulators in countries like India and Germany. The cab service has also battled lawsuits from riders, allegations of underhand ploys from rivals, protests from overseas taxi drivers etc.

As Uber turned five, its CEO Travis Kalanick admitted to the mistakes made by the cab service, which helps people hail a cab via a smartphone app, in the past few years. Kalanick, however, remains optimistic of the service's future.

"I'll be the first to admit I'm not perfect, and neither is this company. Like everyone else, we've made mistakes. But at Uber, we're passionate about learning from them," said Kalanick at the party celebrating Uber's fifth year.

Since its launch in 2010, Uber is now available in 58 countries, encompassing 311 cities. The service has 3,000 full time employees and over a million cab drivers, accounting for more than 1 million rides each day.

The company is optimistic that it will see a growth of 400 percent in 2015 to $2 billion. The rapid growth Uber has seen is validated by the fact that it saw nearly 8.6 million of customer requests (from a total of 17 million over the past five years) in 2015 itself.

In New York alone, Uber boasts of 26,000 drivers. San Francisco, London and Paris have 22,000; 15,000 and 10,000 drivers, respectively.

What makes Uber the "right choice for cities" worldwide is the fact that the service brings to the table more jobs, cleaner air and reduced traffic snarls. The fact that Uber drivers get a lot of job flexibility is also a plus and adds to the attractiveness of being a company employee.

"City by city we go to we've seen it work. If we were able to achieve this much in five years, just image what we could achieve in the next five," let on an optimistic Kalanick.

Uber's long-term vision per Kalanick includes "Fewer people owning cars, fewer cars on the road... less pollution and more prosperity."