Html 为什么我不能将图像环绕文本？

为什么我不能将图像环绕文本将图像置于文本后面

Css代码：

.wrap5{
        background-image: url ('https://upload.wikimedia.org/wikipedia/commons/e/e3/Alto%27s_Adventure_animation_-_01_Chasm.gif');
}

Html代码：

<div class = "wrap5">
<br><br>
<center><h1 style = "color: blue; font-family: monsterrat; letter-spacing: 1px; font-weight: 900;">Are you willing to go on the best journey?</h1></center>
<br><br><br><br>
<center>
<button class = "but" style = "float: center" onclick = "document.getElementById('modal-wrapper2').style.display='block'">Get Started</button>
</center>
<br><br>
<hr>
</div>

---

删除url和左括号之间的空白：

.wrap5{ 背景图片：url'https://upload.wikimedia.org/wikipedia/commons/e/e3/Alto%27s_Adventure_animation_-_01_Chasm.gif'； }