SOURCE

<div id="div1">
	<li>1</li>
	<li>2</li>
	<li>3</li>
	<li>4</li>
	<li>5</li>
	<li>6</li>
	<li>align-content</li>
</div>
<div id="div2">
	<li>1</li>
	<li>2</li>
	<li>3</li>
	<li>4</li>
	<li>5</li>
	<li>6</li>
	<li>align-items</li>
</div>

#div1 li {
	border: 1px solid red;
	list-style: none;
	display: inline-block;
	width: 100px;
}
#div1 {
	display: flex;
	flex-wrap: wrap;
	border: 1px solid black;
	height: 100px;
	justify-content: space-between;
	align-content: center;

}

#div2 li {
	border: 1px solid red;
	list-style: none;
	display: inline-block;
	width: 100px;
}
#div2 {
	display: flex;
	flex-wrap: wrap;
	border: 1px solid black;
	height: 100px;
	justify-content: space-between;
	align-items: center;
}