<div class="container">
  <div class="row">
    <div class="col-md-6">
      <div class="card-group">
        <div class="card">
          <img class="card-img-top" src=".../100px180/" alt="Card image cap">
          <div class="card-body">
            <h5 class="card-title">Card title</h5>
          </div>
        </div>
        <div class="card">
          <img class="card-img-top" src=".../100px180/" alt="Card image cap">
          <div class="card-body">
            <h5 class="card-title">Card title</h5>
          </div>
        </div>
      </div>
    </div>
    <div class="col-md-6">
      <div class="card-group">
        <div class="card">
          <img class="card-img-top" src=".../100px180/" alt="Card image cap">
          <div class="card-body">
            <h5 class="card-title">Card title</h5>
          </div>
        </div>
        <div class="card">
          <img class="card-img-top" src=".../100px180/" alt="Card image cap">
          <div class="card-body">
            <h5 class="card-title">Card title</h5>
          </div>
        </div>
      </div>
    </div>
  </div>
</div>

External CSS

  1. https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.1.2/css/bootstrap.min.css

External JavaScript

This Pen doesn't use any external JavaScript resources.