In the coming weeks, the co-founders of the popular photo-sharing app, Instagram plan to resign. Kevin Systrom, Instagram chief executive, and Mike Krieger, the chief technical officer, informed Instagram’s team and parent company, Facebook on Monday Sept. 24 of their decision. They did not give a reason for stepping down, but explained they will be taking time off after their leave. However, in a statement from Systrom, he and Krieger are “ready for our next chapter,” which hints the two aren’t done creating just yet.

In 2010 the two met, and created a software project built by Systrom himself. This project eventually became the social media platform Instagram, which has over one billion users today. According to Dreamgrow, a social media and marketing website, Instagram is the third most popular social media platform worldwide, behind Facebook and YouTube.

The two are leaving Instagram with serious questions about the future of the app and in a time of crisis for Facebook. Nonetheless, they have been receiving only reassuring messages from many. Mark Zuckerberg, Facebook’s chief executor praised the two, wishing them “all the best” and looked “forward to seeing what they build next.”

Instagram originally caught the eye of Zuckerberg when it’s popularity came about in Silicon Valley. Shortly after negotiation, Facebook bought Instagram for $1 million in cash and stock. This was Facebook’s biggest accession, and it quickly turned Systrom and Krieger into millionaires.

Since then, Instagram has hit record heights and has been valued 10 times more than the $1 million it was bought for. With the step down of the two co-founders, it is uncertain who will take the reins, and lead the popular photo sharing app. Farewell to Kevin Systrom and Mike Krieger.