.carousel-caption {
    text-shadow: 0 2px 5px rgba(0,0,0,.9);
}

.carousel-item-active, 
.carousel-item {
  background-origin: border-box;
  background-repeat: no-repeat;
  background-size: cover;
  background-position: center center;
  height: auto;
  max-height: 600px;
  background-attachment: fixed;
}