<div class="container">
  <div class="el">
    This is some long sentence that cannot wrap, so it overflows the element.
  </div>
</div>
body {
  background-color: #F5F5F5;
  color: #555;
  font-size: 1.1em;
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
}

hr {
  margin: 50px 0;
}

.container {
  margin: 40px auto;
  max-width: 700px;
}

.el {
  background: white;
  border: 1px solid black;
  white-space: nowrap;
  max-width: 450px;
  padding: 0.5em 1em;
}