Tour de France Cambridge to London watched by one million
More than one million people lined the route of the final English stage of the Tour de France, councils estimate.
The third stage from Cambridge, through Essex and on to London was won by German Marcel Kittel on Monday.
Cambridgeshire county councillor Noel Kavanagh said "a tsunami of people descended on Cambridge" for the start.
Essex councillors said it was a "historic day" and Transport for London's (TfL) commissioner described the day as "fantastic".
The 96-mile (155km) flat route took the 196 riders past Cambridge's historical colleges, through Epping Forest and past Buckingham Palace before finishing on the Mall.
Despite Monday's crowds being less than half the number who turned out for the first two stages in Yorkshire at the weekend, Mr Kavanagh described the Cambridge start as "electric".
"In its long and rich history, I don't think Cambridge has ever witnessed such amazing crowds or the incredible excitement and electric atmosphere," he added.
City councillor Richard Johnson said: "We always knew cycling was in the DNA of Cambridge but yesterday we saw faces young and old beaming with excitement as the Tour de France came to town."
London's Transport Commissioner Sir Peter Hendy CBE said the months of planning had ensured the event went smoothly.
The first stage of the 2,277-mile (3,664km) race began in Leeds on Saturday where a sprint finish saw Marcel Kittel claim his first victory on the same day that British rider Mark Cavendish crashed, dashing his hopes of Tour glory.
Sunday's second stage from York to Sheffield was won by Vincenzo Nibali after 124 miles (201km) of punishing roads and hill climbs.
The riders left the UK on Monday for the next stage of the race at Le Touquet-Paris-Plage.
There will be 17 more stages before the race reaches its final destination of Paris on 27 July.