JSFiddle - React, Tailwind, and code Playground

HTML

<div class="bit-3">
  <div class="event" style="background-image: url(https://container25.at/wpdev/wp-content/uploads/2016/06/test.jpg)">
  <div class="inner-text">
      Text inner
  </div>
  </div>
</div>
<div class="bit-3">
  <div class="event" style="background-image: url(https://container25.at/wpdev/wp-content/uploads/2016/06/20170715_mareados.jpg)">
  <div class="inner-text">
      Text inner
  </div>
  </div>
  
</div>

CSS

.bit-3 {
  width: 33.33333%;
  float: left;
  margin-left: 20px;
}

.event {
    margin: 0 auto;
    position: relative;
    border: 2px solid #000000;
    padding-bottom: 150%;
    background-size: cover;
}

.inner-text{
  position:absolute;
  width:100%;
  height:100%;
  text-align:center;
 z-index:1;

}
.event:hover .inner-text{
 background:rgba(255,255,255,0.5)
}