Wordpress get_avatar_url

This is my code:

<span><img class="super-avatar" src="<?php echo get_avatar_url(the_author_meta( 'ID' )); ?>"></img><?php the_author(); ?></span>

The problem I have:

<img class="super-avatar" src="1http://1.gravatar.com/avatar/?s=96&amp;d=mm&amp;r=g">

Why this "number 1" before the url?

@user3571412, if you look your code, you use the_author_meta, it was echo. You must use get_the_author_meta, cause you have echo before.

get_the_author_meta( 'ID' )

So your code

<span><img class="super-avatar" src="<?php echo get_avatar_url(get_the_author_meta( 'ID' )); ?>"></img><?php the_author(); ?></span>