London Underground or Westfield 'bomb plot was foiled'
A plot to bomb the London Underground or the Westfield shopping centre was prevented before the tenth anniversary of the 7 July attacks, a court heard.
Police foiled the plan after Mohammed Rehman used Twitter to ask which target to choose, the Old Bailey was told.
He allegedly bought explosives on eBay and filmed himself testing a bomb.
Mr Rehman, of Radstock Road, Reading, and his wife Sana Ahmed Khan, of Hutton Close, Reading, deny preparing acts of terrorism, on or before 28 May.
Mr Rehman, 25, is also charged with possessing an article for terrorist purposes.
Prosecutor Tony Badenoch QC said the pair had a "common interest" in violent and extreme Islamic ideology and had repeatedly researched 7/7 bombers.
They also had a keen interest in Islamic State, and Mr Rehman's online research showed he approved of their atrocities and "wished to play his own part", jurors were told.
On 12 May, he allegedly posted a public tweet using the handle Silent Bomber, with a profile picture of Jihadi John, saying: "Westfield shopping centre or London underground?"
The same day, Mr Rehman repeatedly trawled YouTube for material about the London bombings and Shehzad Tanweer, one of the 7 July bombers, the court heard.
Counter-terrorism officers spotted Mr Rehman's tweets and went to his home on 28 May, where they seized more than 10kg (22lbs) of urea nitrate - a highly explosive chemical, the jury was told.
The court heard if it had detonated it "would have caused multiple fatalities in a public place".
Almost simultaneously, Ms Khan was arrested at her family home.
Ms Khan kept their Islamic marriage a secret from her family and they lived separately with their parents and siblings, the court heard.