diff --git a/markdown.php b/markdown.php
index ed79197..9713d7d 100644
--- a/markdown.php
+++ b/markdown.php
@@ -386,7 +386,8 @@ class Markdown_Parser {
 		#
 		$block_tags_a_re = 'ins|del';
 		$block_tags_b_re = 'p|div|h[1-6]|blockquote|pre|table|dl|ol|ul|address|'.
-						   'script|noscript|form|fieldset|iframe|math';
+						   'script|noscript|form|fieldset|iframe|math|article|aside|details'.
+						   '|figcaption|figure|footer|header|hgroup|menu|nav|section|summary';
 
 		# Regular expression for the content of a block tag.
 		$nested_tags_level = 4;
@@ -1730,7 +1731,7 @@ class MarkdownExtra_Parser extends Markdown_Parser {
 	### HTML Block Parser ###
 	
 	# Tags that are always treated as block tags:
-	var $block_tags_re = 'p|div|h[1-6]|blockquote|pre|table|dl|ol|ul|address|form|fieldset|iframe|hr|legend';
+	var $block_tags_re = 'p|div|h[1-6]|blockquote|pre|table|dl|ol|ul|address|form|fieldset|iframe|hr|legend|article|aside|details|figcaption|figure|footer|header|hgroup|menu|nav|section|summary';
 	
 	# Tags treated as block tags only if the opening tag is alone on it's line:
 	var $context_block_tags_re = 'script|noscript|math|ins|del';