In memoriam: 7 once-hot startups that shuttered their doors in 2015

As legend has it, 90 percent of startups fail.

While the seven on this list collectively raised nearly $400 million in venture capital, these startups are only a few of the high-profile startups that ended up shuttering their doors in 2015. (CBInsights has a full list of 146 startup failure post-mortems from the past few years.)

Here's how they tried to change the world, and what other startup founders can learn from their demise: