body
{
background-color:#99FFCC;
}
.carousel-inner
 {
 height:30em;
 }
 .carousel-inner .item img {
  min-width: 100%;
  width: 100%;
  min-height: 100%;
  height: 30em;
}
.toppad
{
padding-top:5em;
}
h3 {text-decoration:underline;}
<!-- fill img to div-->
.fill {
    display:flex;
    justify-content:center;
    align-items:center;
    overflow:hidden
}
.fill img {
    flex-shrink:0;
    min-width:100%;
    min-height:100%;
}
<!---->