The documentary series exploring the polar regions averaged 7.93m (31.4%) in the 9pm slot for BBC One, an increase of 1.11m from last week's launch.
Elsewhere on BBC One, The Impressions Show amused 3.71m (15.4%) at 8pm, while Ask Rhod Gilbert attracted 1.71m (13.8%) at 10.45pm.
Over on BBC Two, Great British Food Revival entertained 1.84m (7.6%) at 8pm, while Secret Pakistan secured 1.04m (4.1%) between 9pm and 10pm. Rab C Nesbitt followed with 1.28m (6.3%).
ITV's evening was dominated by Champions League football coverage, which picked up an average of 3.54m (14.5%), including HD numbers, for the Villereal v Manchester City game.
The third part of Channel 4's critically-acclaimed drama series Top Boy picked up 1.01m (5.7%) at 10pm, with a further 166k (1.9%) on +1.
Elsewhere, the channel attracted 1.89m (7.8%) for Kirstie's Handmade Britain in the 8pm slot and Grand Designs collected 2.60m (10.3%) at 9pm. They both picked up 181k and 344k on +1 respectively.
Channel 5's latest instalment of Big Brother amused 1.14m (6.3%) at 10m, while the latest Paul Merton's Adventures pulled in 873k (3.5%) at 9pm.
The Only Way Is Essex was the big multi-channel winner of the evening, drawing 1.10m (5.7%) at 10pm on ITV2. A further 154k (1.6%) caught it on +1.
Overall, BBC One won the evening with 23.3%, ahead of ITV1's 14.8% (including +1 and HD) and Channel 4's 8.0% (including +1 and HD). BBC Two picked up 7.1%, while Channel 5 followed with 4.1%.
BARB ratings data supplied by Attentional