JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//netdna.bootstrapcdn.com/bootstrap/3.1.0/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="//netdna.bootstrapcdn.com/bootstrap/3.1.0/css/bootstrap.min.css">
<div class="container">
    <nav class="navbar navbar-default">
        <div class="navbar-header">
            <button class="navbar-toggle" type="button" data-toggle="collapse" data-target=".js-navbar-collapse">	<span class="sr-only">Toggle navigation</span>
	<span class="icon-bar"></span>
	<span class="icon-bar"></span>
	<span class="icon-bar"></span>

            </button>	<a class="navbar-brand" href="#">MegaMenu</a>

        </div>
        <div class="collapse navbar-collapse js-navbar-collapse">
            <ul class="nav navbar-nav">
                <li class="dropdown mega-dropdown">	<a href="#" class="dropdown-toggle" data-toggle="dropdown">Collection <span class="glyphicon glyphicon-chevron-down pull-right"></span></a>

                    <ul class="dropdown-menu mega-dropdown-menu row">
                        <li class="col-sm-3">
                            <ul>
                                <li class="dropdown-header">Collection 1</li>
                                <div id="myCarousel" class="carousel slide" data-ride="carousel">
                                    <div class="carousel-inner">
                                        <div class="item active"> <a href="#"><img src="http://placehold.it/254x150/3498db/f5f5f5/&text=New+Collection" class="img-responsive" alt="product 1"></a>

                                             <h4><small>Summer dress floral prints</small></h4> 
                                            <button class="btn btn-primary" type="button">49,99 €</button>
                                            <button href="#" class="btn btn-default" type="button"><span class="glyphicon glyphicon-heart"></span> Add to Wishlist</button>
                                        </div>
                                        <!-- End Item -->
       ...

CSS

body {
    font-family:'Open Sans', 'sans-serif';
    background:#f0f0f0;
}
.navbar-nav>li>.dropdown-menu {
    margin-top:20px;
    border-top-left-radius:4px;
    border-top-right-radius:4px;
}
.navbar-default .navbar-nav>li>a {
    width:200px;
    font-weight:bold;
}
.mega-dropdown {
    position: static !important;
    width:100%;
}
.mega-dropdown-menu {
    padding: 20px 0px;
    width: 100%;
    box-shadow: none;
    -webkit-box-shadow: none;
}
.open .dropdown-toggle:after {
    border-bottom: 15px solid #fff;
    border-left: 17px solid transparent;
    border-right: 17px solid transparent;
    content: "";
    left: 163px;
    position: absolute;
    bottom: -21px;
    z-index: 1500;
}
.open .dropdown-toggle span:after {
    border-bottom: 17px solid #ccc;
    border-left: 19px solid transparent;
    border-right: 19px solid transparent;
    content: "";
    left: -10px;
    position: absolute;
    bottom: -41px;
    z-index: 8;
}
.mega-dropdown-menu > li > ul {
    padding: 0;
    margin: 0;
}
.mega-dropdown-menu > li > ul > li {
    list-style: none;
}
.mega-dropdown-menu > li > ul > li > a {
    display: block;
    padding: 3px 20px;
    clear: both;
    font-weight: normal;
    line-height: 1.428571429;
    color: #999;
    white-space: normal;
}
.mega-dropdown-menu > li ul > li > a:hover, .mega-dropdown-menu > li ul > li > a:focus {
    text-decoration: none;
    color: #444;
    background-color: #f5f5f5;
}
.mega-dropdown-menu .dropdown-header {
    color: #428bca;
    font-size: 18px;
    font-weight:bold;
}
.mega-dropdown-menu form {
    margin:3px 20px;
}
.mega-dropdown-menu .form-group {
    margin-bottom: 3px;
}