<nav>
  <ul class="menu">
    <li class="menu-item"><a href="#">Home</a></li>
    <li class="menu-item"><a href="#">Holidays</a><i class="menu-icon fas fa-angle-down"></i>
      <ul class="submenu">
        <li class="submenu-item">
          <ul class="submenu-top">
            <li class="submenu-top-item thumb-list">
              <a href="#" class="submenu-title">Holiday types</a>
              <ul class="submenu-list">
                <li>
                  <span class="submenu-thumbnail"><img src="https://picsum.photos/id/1067/32/32" alt="City breaks"></span>
                  <a href="#">City breaks</a>
                </li>
                <li>
                  <span class="submenu-thumbnail"><img src="https://picsum.photos/id/173/32/32" alt="Adventure tours"></span>
                  <a href="#">Adventure tours</a>
                </li>
                <li>
                  <span class="submenu-thumbnail"><img src="https://picsum.photos/id/1038/32/32" alt="Cruises"></span>
                  <a href="#">Cruises</a>
                </li>
                <li>
                  <span class="submenu-thumbnail"><img src="https://picsum.photos/id/1015/32/32" alt="Beach holidays"></span>
                  <a href="#">Beach holidays</a>
                </li>
              </ul>
            </li>
            <li class="submenu-top-item desc-list">
              <a href="#" class="submenu-title">Holiday packages</a>
              <ul class="submenu-list">
                <li>
                  <a href="#">Families</a>
                  <span class="submenu-desc">Take advantage of our special holiday packages for families.</span>
                </li>
                <li>
                  <a href="#">Students</a>
                  <span class="submenu-desc">Take advantage of our special holiday packages for students.</span>
                </li>
                <li>
                  <a href="#">Couples</a>
                  <span class="submenu-desc">Take advantage of our special holiday packages for couples.</span>
                </li>
              </ul>
            </li>
            <li class="submenu-top-item icon-list">
              <a href="#" class="submenu-title">Our services</a>
              <ul class="submenu-list">
                <li>
                  <i class="submenu-icon fas fa-plane-departure"></i>
                  <a href="#">Plane tickets</a>
                </li>
                <li>
                  <i class="submenu-icon fas fa-car"></i>
                  <a href="#">Car rental</a>
                </li>
                <li>
                  <i class="submenu-icon fas fa-luggage-cart"></i>
                  <a href="#">Luggage pickup</a>
                </li>
                <li>
                  <i class="submenu-icon fas fa-phone-alt"></i>
                  <a href="#">24/7 customer service</a>
                </li>
                <li>
                  <i class="submenu-icon fas fa-dollar-sign"></i>
                  <a href="#">30-day cancellation policy</a>
                </li>
              </ul>
            </li>
            <li class="submenu-top-item">
              <a href="#" class="submenu-title">Last minute offers</a>
              <ul class="submenu-list">
                <li><a href="#">New York</a></li>
                <li><a href="#">Stockholm</a></li>
                <li><a href="#">Madrid</a></li>
                <li><a href="#">Buenos Aires</a></li>
                <li><a href="#">Tokyo</a></li>
              </ul>
            </li>
          </ul>
          <!-- End .submenu-top -->
        </li>
        <!-- End .submenu-item-->
        <li class="submenu-item">
          <a href="#" class="submenu-title submenu-bottom-title">Trending destinations</a>
          <ul class="submenu-bottom">
            <li class="submenu-bottom-item">
              <figure>
                <img class="submenu-img-lg" src="https://picsum.photos/id/1016/640/260">
                <figcaption><a href="#">Mountains</a></figcaption>
              </figure>
            </li>
            <li class="submenu-bottom-item">
              <figure>
                <img class="submenu-img-lg" src="https://picsum.photos/id/1040/640/260">
                <figcaption><a href="#">Castles</a></figcaption>
              </figure>
            </li>
            <li class="submenu-bottom-item">
              <figure>
                <img class="submenu-img-lg" src="https://picsum.photos/id/1039/640/260">
                <figcaption><a href="#">Waterfalls</a></figcaption>
              </figure>
            </li>
            <li class="submenu-bottom-item">
              <figure>
                <img class="submenu-img-lg" src="https://picsum.photos/id/164/640/260">
                <figcaption><a href="#">Historical towns</a></figcaption>
              </figure>
            </li>
          </ul>
        </li>
        <!-- End .submenu-item -->

      </ul>
    </li>
    <li class="menu-item"><a href="#">About</a></li>
    <li class="menu-item"><a href="#">Blog</a></li>
    <li class="menu-item"><a href="#">Contact</a></li>
  </ul>
</nav>
/* General styling */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: sans-serif;
}
body {
  background: #f1f1f1;
}
ul {
    list-style-type: none;
}
a {
    color: white;
    text-decoration: none;
}
.submenu-icon {
    color: #111;
}
a:hover {
    text-decoration: underline;
}
img {
    max-width: 100%;
}
.menu {
    background-color: darkslateblue;
}
.submenu {
   border: 1px solid #ccc;
}
.menu li {
    padding: 10px;
}
.menu-icon {
    color: white;
    margin-left: 10px;
    font-size: 14px;
}
/* Flexbox rules */
.menu {
    display: flex;
    align-items: center;
    text-align: center;
    width: 90vw;
    margin: 10px 5vw;
    height: 60px;
    position: relative;
}
.menu-item {
    flex: 1;
}
.menu-item > a {
    line-height: 40px;
}
.submenu {
    width: 90vw;
    position: absolute;
    top: 60px;
    left: 0;
    text-align: left;
    display: flex;
    flex-direction: column;
}
.submenu-item {
    padding: 15px;
}
.submenu-top {
    display: flex;
    justify-content: space-around;
}
.submenu-bottom {
    display: flex;
}
.submenu-bottom-item {
    flex: 1;
}
/* Submenu general styling */
.submenu-top li {
    padding-left: 0;
}
.submenu a {
    color: #111;
}
.submenu-top-item {
    max-width: 33.333%;
}
.submenu .submenu-title {
    font-weight: bold;
    color: darkslateblue;
}
.submenu .submenu-title:hover {
    text-decoration: none;
}
.submenu-list,
.submenu-bottom {
    margin-top: 10px;
}

/* Submenu: Thumbnail list */
.thumb-list .submenu-list > li {
    display: flex;
    align-items: center;
}
.submenu-thumbnail {
    margin-right: 10px;
}

/* Submenu: Description list */
.desc-list .submenu-list > li {
    display: flex;
    flex-direction: column;
}
.submenu-desc {
    margin-top: 10px;
    color: #555;
}

/* Submenu: Icon list */
.submenu-icon {
    width: 32px;
}

/* Submenu bottom */
.submenu-bottom-title {
    padding-left: 10px;
}
.submenu-bottom figcaption {
    margin-top: 5px;
    font-weight: bold;
}
.submenu-bottom a:hover {
    text-decoration: none;
}
/* Hover rule */
.submenu { 
    display: none;
}
.menu-item:hover .submenu {
    display: flex;
}
.menu-item:hover > a {
    text-decoration: underline;
}

External CSS

  1. https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.9.0/css/all.min.css

External JavaScript

This Pen doesn't use any external JavaScript resources.