* Cards are bordered boxes with a bit of padding around the content inside them, which can be used to conveniently display a specific set of information.
** To create a basic Bootstrap 4 card, you need to create a `<div>` container with the class `.card` and inside another `<div>` container with the class of `.card-body`**
The structure of the card can be enhanced by the addition of a header and a footer. To add one of these elements, you have to create a `<div>` container with the `.card-header` or `.card-footer` class.
* You may also use specific classes for displaying images in cards.
* There are two classes for this purpose: card-img-top, which places an image on the top of the card, and card-img-bottom, which places the image on the bottom, both of them fitting them to the rounded border of the card neatly.
* These classes have to be used with the ```<img>``` tag inside a card to work properly.
* Keep in mind, that if you want an image to span the entire width, you would add the image container outside of the ```<div>``` container with the card-body class.
* For making an image into the background of the card and displaying the text on top of it you need to use the class card-img-overlay on the content, which you want to display over the image, instead of using the card-body class.