You can get quite close to the exhibits and touching is fine
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/130275500@N02">G B_NZ</a>
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/130275500@N02/25871422273/">Chinese Air Force Mig-15, Beijing Aviation Museum</a>