Get all categories with sub-categories in Magento
<?php $_helper = Mage::helper('catalog/category') ?>
<?php $_categories = $_helper->getStoreCategories() ?>
<?php if (count($_categories) > 0): ?>
<ul class="nav navbar-nav">
<?php foreach($_categories as $_category): ?>
<li class="dropdown dropdown100">
<a href="<?php echo $_helper->getCategoryUrl($_category) ?>" class="dropdown-toggle">
<?php echo $_category->getName() ?>
</a>
<?php $_category = Mage::getModel('catalog/category')->load($_category->getId()) ?>
<?php $_subcategories = $_category->getChildrenCategories() ?>
<?php if (count($_subcategories) > 0): ?>
<ul class="dropdown-menu">
<li>
<div class="header-navigation-content">
<div class="row">
<?php foreach($_subcategories as $_subcategory): ?>
<div class="col-md-2">
<h3><?php echo $_subcategory->getName() ?></h3>
<?php $_subcategories = $_subcategory->getChildrenCategories() ?>
<?php if (count($_subcategories) > 0): ?>
<ul>
<?php foreach($_subcategories as $_subcategory): ?>
<li>
<a href="<?php echo $_helper->getCategoryUrl($_subcategory) ?>">
<?php echo $_subcategory->getName(); ?>
</a>
</li>
<?php endforeach; ?>
</ul>
<?php endif; ?>
</div>
<?php endforeach; ?>
</div>
</div>
</li>
</ul>
<?php endif; ?>
</li>
<?php endforeach; ?>
</ul>
<?php endif; ?>
