Tightrope walker Nik Wallenda has successfully completed back-to-back high-wire walks above Chicago, watched by thousands of people.

Nik Wallenda, 35, achieved the two skyscraper crossings without a safety net or a harness.

He first walked up a steep incline between buildings either side of the Chicago River.

Nik Wallenda achieved the Chicago skyscraper crossings without a safety net or a harness (photo Discovery)

Then, blindfolded, Nik Wallenda crossed between the two Marina City towers.

It took him 6 minutes 52 seconds to complete the first stage 500ft above the ground – in winds that were gusting at up to 25mph.

Nik Wallenda then completed the 94ft between the two Marina City Towers in one minute 17 seconds.

The stunts were televised with a 10-second delay in case he fell.

On the ground, thousands cheered Nik Wallenda.

The tightrope walker – again blindfolded – then answered reporters’ questions.

Nik Wallenda, a seventh-generation tightrope walker, has already walked across both the Grand Canyon and the Niagara Falls on tightropes.