Two of the most famous climbs in the cycling world were included in my 50 km cycle ride today.
The first, the Cauberg, is a 1.2 km ascent out of the picturesque Dutch town of Valkenburg.
The elevation gain is 65 metres and in places the gradient is over 11.6%.
I must admit that I stopped twice to catch my breath but managed to cycle every metre rather than get off and walk.
Valkenburg is a well known cycling town in South Limburg and is home to the annual running of the Amstel Gold Race.
My route today included many of the roads, lanes and hills this race is usually run on.
The second hill, the Bemelerberg, rises for 2 km out of the town of Bemelen.
Although not as steep as the Cauberg, it still challenges legs and lungs for the entire climb.
The elevation gain is 66 metres at a maximum grade of 6.3%.
Bemelerberg is a nature reserve and about halfway up the hill can be seen the white limestone rock.
This has been exposed by many years of erosion caused by animal grazing.
My ride back home was somewhat easier, mostly on unfamiliar back roads through the rolling hills of South Limburg.