The best quote on Tiananmen Square in Lonely Planet:
Bicycles cannot be ridden across Tiananmen Square (apparently tanks are OK), but you can walk the bike.There is also a gate (Qianmen) at the edge of Tiananmen square, which you can go upstairs to get a good view of the line to see Mao.

Mei on the stairs of the QianMen.

Mei in Tiananmen Square in front of Tiananmen.