<div class="container"></div>

.container {
  background-image: url("https://images.unsplash.com/photo-1469474968028-56623f02e42e?auto=format&fit=crop&w=1953&q=80");
  height: 90vh;
  width: 90vw;
  background-size: cover;
  background-position: center;
}

/* Additional Styling */
html,
body {
  padding: 0;
  margin: 0;
  height: 100vh;
  width: 100vw;
  display: flex;
  justify-content: center;
  align-items: center;
}