diff --git a/core/includes/common.inc b/core/includes/common.inc
index 90641b6..0fb232e 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -2214,11 +2214,17 @@ function drupal_add_js($data = NULL, $options = NULL) {
           $scriptPath = $GLOBALS['script_path'];
           $pathPrefix = '';
           url('', array('script' => &$scriptPath, 'prefix' => &$pathPrefix));
+          $current_path = current_path();
+          $current_path_is_admin = FALSE;
+          if (!defined('MAINTENANCE_MODE') || MAINTENANCE_MODE !== 'update') {
+            $current_path_is_admin = path_is_admin($current_path);
+          }
           $javascript['settings']['data'][] = array(
             'basePath' => base_path(),
             'scriptPath' => $scriptPath,
             'pathPrefix' => $pathPrefix,
-            'currentPath' => current_path(),
+            'currentPath' => $current_path,
+            'currentPathIsAdmin' =>  $current_path_is_admin,
           );
         }
         // All JavaScript settings are placed in the header of the page with
diff --git a/core/modules/block/lib/Drupal/block/Controller/BlockController.php b/core/modules/block/lib/Drupal/block/Controller/BlockController.php
index c735ba0..0536022 100644
--- a/core/modules/block/lib/Drupal/block/Controller/BlockController.php
+++ b/core/modules/block/lib/Drupal/block/Controller/BlockController.php
@@ -30,6 +30,13 @@ public function demo($theme) {
     return array(
       '#title' => String::checkPlain($themes[$theme]->info['name']),
       '#attached' => array(
+        'js' => array(
+          array(
+            // Let JavaScript know this really is an admin page.
+            'data' => array('currentPathIsAdmin' => TRUE),
+            'type' => 'setting',
+          )
+        ),
         'library' => array(
           array('block', 'drupal.block.admin'),
         ),
diff --git a/core/modules/toolbar/css/toolbar.icons.css b/core/modules/toolbar/css/toolbar.icons.css
index b10de97..a0cfce2 100644
--- a/core/modules/toolbar/css/toolbar.icons.css
+++ b/core/modules/toolbar/css/toolbar.icons.css
@@ -319,7 +319,18 @@
   background-image: url("../../../misc/icons/787878/twistie-up.png");
   background-size: auto auto;
 }
-
+.toolbar .toolbar-icon-escape:before {
+  background-image: url("../../../misc/icons/bebebe/chevron-disc-left.svg");
+}
+.no-svg .toolbar .toolbar-icon-escape:before {
+  background-image: url("../../../misc/icons/bebebe/chevron-disc-left.png");
+}
+[dir="rtl"] .toolbar .toolbar-icon-escape:before {
+  background-image: url("../../../misc/icons/bebebe/chevron-disc-right.svg");
+}
+[dir="rtl"] .no-svg .toolbar .toolbar-icon-escape:before {
+  background-image: url("../../../misc/icons/bebebe/chevron-disc-right.png");
+}
 /**
  * Orientation toggle.
  */
diff --git a/core/modules/toolbar/js/escapeAdmin.js b/core/modules/toolbar/js/escapeAdmin.js
new file mode 100644
index 0000000..4343ce1
--- /dev/null
+++ b/core/modules/toolbar/js/escapeAdmin.js
@@ -0,0 +1,36 @@
+(function ($, Drupal, drupalSettings) {
+
+  "use strict";
+
+  var escapeAdminPage = sessionStorage.getItem('escapeAdminPage');
+
+  if (!drupalSettings.currentPathIsAdmin) {
+    sessionStorage.setItem('escapeAdminPage', drupalSettings.currentPath);
+  }
+
+  Drupal.behaviors.escapeAdmin = {
+    attach: function () {
+      var $toolbarEscape = $('[data-toolbar-escape]').once('escapeAdmin');
+      if ($toolbarEscape.length) {
+        if (drupalSettings.currentPathIsAdmin && escapeAdminPage) {
+          $toolbarEscape
+            .removeClass('toolbar-icon-home')
+            .addClass('toolbar-icon-escape')
+            .attr({
+              'href': Drupal.url(escapeAdminPage),
+              'title': Drupal.t('Return to site content')
+            })
+            .text(Drupal.t('Back to site'));
+
+          // Escape admin when hitting Esc key.
+          $(window).on('keydown', function (event) {
+            if (event.keyCode === 27) {
+              window.location = Drupal.url(escapeAdminPage);
+            }
+          });
+        }
+      }
+    }
+  };
+
+})(jQuery, Drupal, drupalSettings);
diff --git a/core/modules/toolbar/toolbar.module b/core/modules/toolbar/toolbar.module
index 85bfafa..56f0012 100644
--- a/core/modules/toolbar/toolbar.module
+++ b/core/modules/toolbar/toolbar.module
@@ -416,9 +416,15 @@ function toolbar_toolbar() {
         'attributes' => array(
           'title' => t('Home page'),
           'class' => array('toolbar-icon', 'toolbar-icon-home'),
+          'data-toolbar-escape' => TRUE,
         ),
       ),
     ),
+    '#attached' => array(
+      'library' => array(
+        array('toolbar', 'toolbar.escapeAdmin'),
+      ),
+    ),
     '#weight' => -20,
   );
 
@@ -609,6 +615,18 @@ function toolbar_library_info() {
       array('system', 'jquery.once'),
     ),
   );
+  $libraries['toolbar.escapeAdmin'] = array(
+    'title' => 'Provides a button to escape the admin.',
+    'version' => \Drupal::VERSION,
+    'js' => array(
+      drupal_get_path('module', 'toolbar') . '/js/escapeAdmin.js',
+    ),
+    'dependencies' => array(
+      array('system', 'jquery'),
+      array('system', 'drupal'),
+      array('system', 'drupalSettings'),
+    ),
+  );
 
   return $libraries;
 }