Downloads disappeared from my desktop

out of blue, "downloads" icon disappeared - don't know how happened. next applications & documents folders in bottom right, vanished. have idea how back?

thanks!

os 10.6.8

 

restoring folders dock

 

Forums Macs Desktops iMac

• iPhone
• Mac OS & System Software
• iPad
• Apple Watch
• Notebooks
• iTunes
• Apple ID
• iCloud
• Desktop Computers
• Apple Music
• Professional Applications
• iPod
• iWork
• Apple TV
• iLife
• Wireless