Possible Clues:

• Landscape is Turner's first in London museum
• Third word of 19-Across
• ''Hasta la ___!''
• A view as seen through a long narrow opening
• Western scene, e.g.
• By way of a way in prospect
• Nice view
• Clip from TV is taped for Panorama
• Buena ___ (Mexican-American battle site)
• Prospect of one way into V & A