Más ejercicios en pablomonteserin.com 
<!doctype html>
<html lang="en">

<head>
  <!-- Required meta tags -->
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
  <meta name="robots" content="noindex, follow">
  <!-- Bootstrap CSS -->
  <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.0.1/dist/css/bootstrap.min.css" rel="stylesheet">


  <title>Hello, world!</title>
  <style>
    .row * {
      border: 4px solid black
    }
  </style>
</head>

<body>
  <br>
  <div class="container">
    <div class="row justify-content-start">
      <div class="col-2">1</div>
      <div class="col-2">2</div>
    </div>
  </div>

</body>

</html>